diff --git a/app/components/dossiers/individual_form_component.rb b/app/components/dossiers/individual_form_component.rb
new file mode 100644
index 000000000..59ce27d9f
--- /dev/null
+++ b/app/components/dossiers/individual_form_component.rb
@@ -0,0 +1,11 @@
+class Dossiers::IndividualFormComponent < ApplicationComponent
+  delegate :for_tiers?, to: :@dossier
+
+  def initialize(dossier:)
+    @dossier = dossier
+  end
+
+  def email_notifications?(individual)
+    individual.object.notification_method == Individual.notification_methods[:email]
+  end
+end
diff --git a/app/components/dossiers/individual_form_component/individual_form_component.en.yml b/app/components/dossiers/individual_form_component/individual_form_component.en.yml
new file mode 100644
index 000000000..fbaffd2e5
--- /dev/null
+++ b/app/components/dossiers/individual_form_component/individual_form_component.en.yml
@@ -0,0 +1,7 @@
+---
+en:
+  self_title: Your identity
+  callout_text: "You are acting as a proxy for a principal, either professionally (such as accountant, lawyer, civil servant…) or personally (family). Make sure to respect the conditions of"
+  callout_link: Articles 1984 and following of the Civil Code.
+  callout_link_title: Articles 1984 and following of the Civil Code
+  beneficiaire_title: "Identity of the beneficiary"
diff --git a/app/components/dossiers/individual_form_component/individual_form_component.fr.yml b/app/components/dossiers/individual_form_component/individual_form_component.fr.yml
new file mode 100644
index 000000000..86512c87b
--- /dev/null
+++ b/app/components/dossiers/individual_form_component/individual_form_component.fr.yml
@@ -0,0 +1,7 @@
+---
+fr:
+  self_title: Votre identité
+  callout_text: Vous agissez en tant que mandataire, soit professionnellement (comme expert-comptable, avocat, agent public…) soit personnellement (famille). Assurez-vous de respecter les conditions
+  callout_link: des Articles 1984 et suivants du Code civil.
+  callout_link_title: Articles 1984 et suivants du Code civil
+  beneficiaire_title: Identité du bénéficiaire
diff --git a/app/components/dossiers/individual_form_component/individual_form_component.html.haml b/app/components/dossiers/individual_form_component/individual_form_component.html.haml
new file mode 100644
index 000000000..97b91976c
--- /dev/null
+++ b/app/components/dossiers/individual_form_component/individual_form_component.html.haml
@@ -0,0 +1,76 @@
+= form_for @dossier, url: update_identite_dossier_path(@dossier), html: { id: 'identite-form', class: "form",  "data-controller" => "for-tiers" } do |f|
+  - if for_tiers?
+    .fr-alert.fr-alert--info.fr-mb-2w
+      %p.fr-notice__text
+        = t('.callout_text')
+        = link_to(t('.callout_link'),
+                'https://www.legifrance.gouv.fr/codes/section_lc/LEGITEXT000006070721/LEGISCTA000006136404/#LEGISCTA000006136404',
+                title: helpers.new_tab_suffix(t('.callout_link_title')),
+                **helpers.external_link_attributes)
+
+    %fieldset.fr-fieldset.mandataire-infos
+      %legend.fr-fieldset__legend--regular.fr-fieldset__legend
+        %h2.fr-h4
+          = t('.self_title')
+
+      .fr-fieldset__element.fr-fieldset__element--short-text
+        = render Dsfr::InputComponent.new(form: f, attribute: :mandataire_first_name, opts: { autocomplete: 'given-name' })
+
+      .fr-fieldset__element.fr-fieldset__element--short-text
+        = render Dsfr::InputComponent.new(form: f, attribute: :mandataire_last_name, opts: { autocomplete: 'family-name' })
+
+  = f.fields_for :individual, include_id: false do |individual|
+    %fieldset.fr-fieldset.fr-mb-0.individual-infos
+      %legend.fr-fieldset__legend--regular.fr-fieldset__legend
+        %h2.fr-h4
+          - if for_tiers?
+            = t('.beneficiaire_title')
+          - else
+            = t('.self_title')
+
+      .fr-fieldset__element.fr-mb-0
+        %fieldset.fr-fieldset
+          %legend.fr-fieldset__legend--regular.fr-fieldset__legend
+            = t('activerecord.attributes.individual.gender')
+            = render EditableChamp::AsteriskMandatoryComponent.new
+
+          .fr-fieldset__element
+            .fr-radio-group
+              = individual.radio_button :gender, Individual::GENDER_FEMALE, required: true, id: "identite_champ_radio_#{Individual::GENDER_FEMALE}"
+              %label.fr-label{ for: "identite_champ_radio_#{Individual::GENDER_FEMALE}" }
+                = Individual.human_attribute_name('gender.female')
+          .fr-fieldset__element
+            .fr-radio-group
+              = individual.radio_button :gender, Individual::GENDER_MALE, required: true, id: "identite_champ_radio_#{Individual::GENDER_MALE}"
+              %label.fr-label{ for: "identite_champ_radio_#{Individual::GENDER_MALE}" }
+                = Individual.human_attribute_name('gender.male')
+      .fr-fieldset__element.fr-mb-0
+        %fieldset.fr-fieldset.width-100
+          .fr-fieldset__element.fr-fieldset__element--short-text
+            = render Dsfr::InputComponent.new(form: individual, attribute: :prenom, opts: { autocomplete: (for_tiers? ? false : 'given-name') })
+          .fr-fieldset__element.fr-fieldset__element--short-text
+            = render Dsfr::InputComponent.new(form: individual, attribute: :nom, opts: { autocomplete: (for_tiers? ? false : 'family-name') })
+
+          - if @dossier.procedure.ask_birthday?
+            .fr-fieldset__element
+              = render Dsfr::InputComponent.new(form: individual, attribute: :birthdate, input_type: :date_field,
+                  opts: { placeholder: 'Format : AAAA-MM-JJ', max: Date.today.iso8601, min: "1900-01-01", autocomplete: 'bday' })
+
+    - if for_tiers?
+      %fieldset.fr-fieldset
+        %legend.fr-fieldset__legend--regular.fr-fieldset__legend
+          = t('activerecord.attributes.individual.notification_method')
+          = render EditableChamp::AsteriskMandatoryComponent.new
+
+        - Individual.notification_methods.each do |method, _|
+          .fr-fieldset__element
+            .fr-radio-group
+              = individual.radio_button :notification_method, method, required: true, id: "notification_method_#{method}", "data-action" => "for-tiers#toggleEmailInput", "data-for-tiers-target" => "notificationMethod"
+              %label.fr-label{ for: "notification_method_#{method}" }
+                = t("activerecord.attributes.individual.notification_methods.#{method}")
+
+
+      .fr-fieldset__element.fr-fieldset__element--short-text{ "data-for-tiers-target" => "emailContainer", class: class_names(hidden: !email_notifications?(individual)) }
+        = render Dsfr::InputComponent.new(form: individual, attribute: :email, input_type: :email_field, opts: { "data-for-tiers-target" => "emailInput" })
+
+  = f.submit t('views.users.dossiers.identite.continue'), class: "fr-btn"
diff --git a/app/controllers/users/dossiers_controller.rb b/app/controllers/users/dossiers_controller.rb
index 92f4d00a8..08ecd2f55 100644
--- a/app/controllers/users/dossiers_controller.rb
+++ b/app/controllers/users/dossiers_controller.rb
@@ -135,6 +135,13 @@ module Users
       @dossier = dossier
       @user = current_user
       @no_description = true
+
+      respond_to do |format|
+        format.html
+        format.turbo_stream do
+          @dossier.update_columns(params.require(:dossier).permit(:for_tiers).to_h)
+        end
+      end
     end
 
     def update_identite
diff --git a/app/dashboards/procedure_dashboard.rb b/app/dashboards/procedure_dashboard.rb
index b7d889d37..134208df4 100644
--- a/app/dashboards/procedure_dashboard.rb
+++ b/app/dashboards/procedure_dashboard.rb
@@ -46,6 +46,7 @@ class ProcedureDashboard < Administrate::BaseDashboard
     max_duree_conservation_dossiers_dans_ds: Field::Number,
     estimated_duration_visible: Field::Boolean,
     piece_justificative_multiple: Field::Boolean,
+    for_tiers_enabled: Field::Boolean,
     replaced_by_procedure_id: Field::String,
     tags: Field::Text,
     template: Field::Boolean
@@ -109,6 +110,7 @@ class ProcedureDashboard < Administrate::BaseDashboard
     :max_duree_conservation_dossiers_dans_ds,
     :estimated_duration_visible,
     :piece_justificative_multiple,
+    :for_tiers_enabled,
     :replaced_by_procedure_id
   ].freeze
 
@@ -121,6 +123,7 @@ class ProcedureDashboard < Administrate::BaseDashboard
     :max_duree_conservation_dossiers_dans_ds,
     :estimated_duration_visible,
     :piece_justificative_multiple,
+    :for_tiers_enabled,
     :replaced_by_procedure_id
   ].freeze
 
diff --git a/app/javascript/controllers/for_tiers_controller.ts b/app/javascript/controllers/for_tiers_controller.ts
index 7aa955da0..6ec3a821c 100644
--- a/app/javascript/controllers/for_tiers_controller.ts
+++ b/app/javascript/controllers/for_tiers_controller.ts
@@ -1,87 +1,32 @@
+import { toggle } from '@utils';
 import { ApplicationController } from './application_controller';
 
+function onVisibleEnableInputs(element: HTMLInputElement) {
+  element.disabled = false;
+  element.required = true;
+}
+
+function onHiddenDisableInputs(element: HTMLInputElement) {
+  element.disabled = true;
+  element.required = false;
+}
+
 export class ForTiersController extends ApplicationController {
-  static targets = [
-    'mandataireFirstName',
-    'mandataireLastName',
-    'forTiers',
-    'mandataireBlock',
-    'beneficiaireNotificationBlock',
-    'email',
-    'notificationMethod',
-    'mandataireTitle',
-    'beneficiaireTitle',
-    'emailInput'
-  ];
+  static targets = ['emailContainer', 'emailInput', 'notificationMethod'];
 
-  declare mandataireFirstNameTarget: HTMLInputElement;
-  declare mandataireLastNameTarget: HTMLInputElement;
-  declare forTiersTargets: NodeListOf<HTMLInputElement>;
-  declare mandataireBlockTarget: HTMLElement;
-  declare beneficiaireNotificationBlockTarget: HTMLElement;
   declare notificationMethodTargets: NodeListOf<HTMLInputElement>;
-  declare emailTarget: HTMLInputElement;
-  declare mandataireTitleTarget: HTMLElement;
-  declare beneficiaireTitleTarget: HTMLElement;
-  declare emailInput: HTMLInputElement;
+  declare emailContainerTarget: HTMLElement;
+  declare emailInputTarget: HTMLInputElement;
 
-  connect() {
-    const emailInputElement = this.emailTarget.querySelector('input');
-    if (emailInputElement) {
-      this.emailInput = emailInputElement;
-    }
-    this.toggleFieldRequirements();
-    this.addAllEventListeners();
-  }
-
-  addAllEventListeners() {
-    this.forTiersTargets.forEach((radio) => {
-      radio.addEventListener('change', () => this.toggleFieldRequirements());
-    });
-    this.notificationMethodTargets.forEach((radio) => {
-      radio.addEventListener('change', () => this.toggleEmailInput());
-    });
-  }
-
-  toggleFieldRequirements() {
-    const forTiersSelected = this.isForTiersSelected();
-    this.toggleDisplay(this.mandataireBlockTarget, forTiersSelected);
-    this.toggleDisplay(
-      this.beneficiaireNotificationBlockTarget,
-      forTiersSelected
-    );
-    this.mandataireFirstNameTarget.required = forTiersSelected;
-    this.mandataireLastNameTarget.required = forTiersSelected;
-    this.mandataireTitleTarget.classList.toggle('hidden', forTiersSelected);
-    this.beneficiaireTitleTarget.classList.toggle('hidden', !forTiersSelected);
-    this.notificationMethodTargets.forEach((radio) => {
-      radio.required = forTiersSelected;
-    });
-
-    this.toggleEmailInput();
-  }
-
-  isForTiersSelected() {
-    return Array.from(this.forTiersTargets).some(
-      (radio) => radio.checked && radio.value === 'true'
-    );
-  }
-
-  toggleDisplay(element: HTMLElement, shouldDisplay: boolean) {
-    element.classList.toggle('hidden', !shouldDisplay);
-  }
   toggleEmailInput() {
     const isEmailSelected = this.isEmailSelected();
-    const forTiersSelected = this.isForTiersSelected();
 
-    if (this.emailInput) {
-      this.emailInput.required = forTiersSelected && isEmailSelected;
+    toggle(this.emailContainerTarget, isEmailSelected);
 
-      if (!isEmailSelected) {
-        this.emailInput.value = '';
-      }
-
-      this.toggleDisplay(this.emailTarget, forTiersSelected && isEmailSelected);
+    if (isEmailSelected) {
+      onVisibleEnableInputs(this.emailInputTarget);
+    } else {
+      onHiddenDisableInputs(this.emailInputTarget);
     }
   }
 
diff --git a/app/models/individual.rb b/app/models/individual.rb
index c3d92b9eb..76257a20c 100644
--- a/app/models/individual.rb
+++ b/app/models/individual.rb
@@ -15,7 +15,7 @@ class Individual < ApplicationRecord
                                   if: -> { dossier.for_tiers? },
                                   on: :update
 
-  validates :email, presence: true, if: -> { dossier.for_tiers? && self.email? }, on: :update
+  validates :email, strict_email: true, presence: true, if: -> { dossier.for_tiers? && self.email? }, on: :update
 
   GENDER_MALE = "M."
   GENDER_FEMALE = 'Mme'
diff --git a/app/views/users/dossiers/identite.html.haml b/app/views/users/dossiers/identite.html.haml
index ed0f5f432..8f79877b4 100644
--- a/app/views/users/dossiers/identite.html.haml
+++ b/app/views/users/dossiers/identite.html.haml
@@ -3,98 +3,28 @@
 = render partial: "shared/dossiers/submit_is_over", locals: { dossier: @dossier }
 
 - if !dossier_submission_is_closed?(@dossier)
-  = form_for @dossier, url: update_identite_dossier_path(@dossier), html: { class: "form",  "data-controller" => "for-tiers" } do |f|
+  - if @dossier.procedure.for_tiers_enabled?
+    = form_for @dossier, url: identite_dossier_path(@dossier), method: :patch, html: { class: "form" }, data: {turbo: true, controller: :autosubmit} do |f|
 
-    %fieldset#radio-rich-hint.fr-fieldset{ "aria-labelledby" => "radio-rich-hint-legend radio-rich-hint-messages" }
-      %legend#radio-rich-hint-legend.fr-fieldset__legend--regular.fr-fieldset__legend
-        = t('views.users.dossiers.identite.legend')
+      %fieldset#radio-rich-hint.fr-fieldset{ "aria-labelledby" => "radio-rich-hint-legend radio-rich-hint-messages" }
+        %legend#radio-rich-hint-legend.fr-fieldset__legend--regular.fr-fieldset__legend
+          = t('views.users.dossiers.identite.legend')
 
-      .fr-fieldset__element
-        .fr-radio-group.fr-radio-rich
-          = f.radio_button :for_tiers, false, required: true, id: "radio-self-manage", "data-action" => "click->for-tiers#toggleFieldRequirements", "data-for-tiers-target" => "forTiers"
-          %label.fr-label{ for: "radio-self-manage" }
-            = t('activerecord.attributes.dossier.for_tiers.false')
-          .fr-radio-rich__img
-            %span.fr-icon-user-fill
-      .fr-fieldset__element
-        .fr-radio-group.fr-radio-rich
-          = f.radio_button :for_tiers, true, required: true, id: "radio-tiers-manage", "data-action" => "click->for-tiers#toggleFieldRequirements", "data-for-tiers-target" => "forTiers"
-          %label.fr-label{ for: "radio-tiers-manage" }
-            = t('activerecord.attributes.dossier.for_tiers.true')
-          .fr-radio-rich__img
-            %span.fr-icon-parent-fill
+        .fr-fieldset__element
+          .fr-radio-group.fr-radio-rich
+            = f.radio_button :for_tiers, false, required: true, id: "radio-self-manage"
+            %label.fr-label{ for: "radio-self-manage" }
+              = t('activerecord.attributes.dossier.for_tiers.false')
+            .fr-radio-rich__img
+              %span.fr-icon-user-fill
+        .fr-fieldset__element
+          .fr-radio-group.fr-radio-rich
+            = f.radio_button :for_tiers, true, required: true, id: "radio-tiers-manage"
+            %label.fr-label{ for: "radio-tiers-manage" }
+              = t('activerecord.attributes.dossier.for_tiers.true')
+            .fr-radio-rich__img
+              %span.fr-icon-parent-fill
 
-    .mandataire-infos{ "data-for-tiers-target" => "mandataireBlock" }
-      .fr-alert.fr-alert--info.fr-mb-2w
-        %p.fr-notice__text
-          = t('views.users.dossiers.identite.callout_text')
-          = link_to(t('views.users.dossiers.identite.callout_link'),
-                  'https://www.legifrance.gouv.fr/codes/section_lc/LEGITEXT000006070721/LEGISCTA000006136404/#LEGISCTA000006136404',
-                  title: new_tab_suffix(t('views.users.dossiers.identite.callout_link_title')),
-                  **external_link_attributes)
+        = f.submit t('views.users.dossiers.identite.continue'), class: 'visually-hidden'
 
-
-      %fieldset.fr-fieldset
-        %legend.fr-fieldset__legend--regular.fr-fieldset__legend
-          %h2.fr-h4= t('views.users.dossiers.identite.self_title')
-
-        .fr-fieldset__element.fr-fieldset__element--short-text
-          = render Dsfr::InputComponent.new(form: f, attribute: :mandataire_first_name, opts: { "data-for-tiers-target" => "mandataireFirstName" })
-
-        .fr-fieldset__element.fr-fieldset__element--short-text
-          = render Dsfr::InputComponent.new(form: f, attribute: :mandataire_last_name, opts: { "data-for-tiers-target" => "mandataireLastName" })
-
-    = f.fields_for :individual, include_id: false do |individual|
-      .individual-infos
-        %fieldset.fr-fieldset
-          %legend.fr-fieldset__legend--regular.fr-fieldset__legend{ "data-for-tiers-target" => "mandataireTitle" }
-            %h2.fr-h4= t('views.users.dossiers.identite.self_title')
-
-          %legend.fr-fieldset__legend--regular.fr-fieldset__legend.hidden{ "data-for-tiers-target" => "beneficiaireTitle" }
-            %h2.fr-h4= t('views.users.dossiers.identite.beneficiaire_title')
-
-
-          %legend.fr-fieldset__legend--regular.fr-fieldset__legend
-            = t('activerecord.attributes.individual.gender')
-            = render EditableChamp::AsteriskMandatoryComponent.new
-          .fr-fieldset__element
-            .fr-radio-group
-              = individual.radio_button :gender, Individual::GENDER_FEMALE, required: true, id: "identite_champ_radio_#{Individual::GENDER_FEMALE}"
-              %label.fr-label{ for: "identite_champ_radio_#{Individual::GENDER_FEMALE}" }
-                = Individual.human_attribute_name('gender.female')
-          .fr-fieldset__element
-            .fr-radio-group
-              = individual.radio_button :gender, Individual::GENDER_MALE, required: true, id: "identite_champ_radio_#{Individual::GENDER_MALE}"
-              %label.fr-label{ for: "identite_champ_radio_#{Individual::GENDER_MALE}" }
-                = Individual.human_attribute_name('gender.male')
-
-          .fr-fieldset__element.fr-fieldset__element--short-text
-            = render Dsfr::InputComponent.new(form: individual, attribute: :prenom, opts: { autocomplete: 'given-name' })
-
-          .fr-fieldset__element.fr-fieldset__element--short-text
-            = render Dsfr::InputComponent.new(form: individual, attribute: :nom, opts: { autocomplete: 'family-name' })
-
-        %fieldset.fr-fieldset{ "data-for-tiers-target" => "beneficiaireNotificationBlock" }
-          %legend.fr-fieldset__legend--regular.fr-fieldset__legend
-            = t('activerecord.attributes.individual.notification_method')
-            = render EditableChamp::AsteriskMandatoryComponent.new
-
-          - Individual.notification_methods.each do |method, _|
-            .fr-fieldset__element
-              .fr-radio-group
-                = individual.radio_button :notification_method, method, id: "notification_method_#{method}", "data-action" => "for-tiers#toggleFieldRequirements", "data-for-tiers-target" => "notificationMethod"
-                %label.fr-label{ for: "notification_method_#{method}" }
-                  = t("activerecord.attributes.individual.notification_methods.#{method}")
-
-
-          .fr-fieldset__element.fr-fieldset__element--short-text.hidden{ "data-for-tiers-target" => "email" }
-            = render Dsfr::InputComponent.new(form: individual, attribute: :email)
-
-
-        - if @dossier.procedure.ask_birthday?
-          .fr-fieldset__element
-            = render Dsfr::InputComponent.new(form: individual, attribute: :birthdate, input_type: :date_field,
-              opts: { placeholder: 'Format : AAAA-MM-JJ', max: Date.today.iso8601, min: "1900-01-01", autocomplete: 'bday' })
-
-
-    = f.submit t('views.users.dossiers.identite.continue'), class: "fr-btn"
+  = render Dossiers::IndividualFormComponent.new(dossier: @dossier)
diff --git a/app/views/users/dossiers/identite.turbo_stream.haml b/app/views/users/dossiers/identite.turbo_stream.haml
new file mode 100644
index 000000000..b7c032d59
--- /dev/null
+++ b/app/views/users/dossiers/identite.turbo_stream.haml
@@ -0,0 +1 @@
+= turbo_stream.replace 'identite-form', render(Dossiers::IndividualFormComponent.new(dossier: @dossier))
diff --git a/config/locales/en.yml b/config/locales/en.yml
index f6c424ccb..ed95ea081 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -423,11 +423,6 @@ en:
         archived_dossier: "Your file will be kept %{duree_conservation_dossiers_dans_ds} more months"
         identite:
           legend: 'This file is:'
-          self_title: Your identity
-          callout_text: "You are acting as a proxy for a principal, either professionally (such as accountant, lawyer, civil servant…) or personally (family). Make sure to respect the conditions of"
-          callout_link: Articles 1984 and following of the Civil Code.
-          callout_link_title: Articles 1984 and following of the Civil Code
-          beneficiaire_title: "Identity of the beneficiary"
           identity_siret: Identify your establishment
           civility: Civility
           first_name: First Name
diff --git a/config/locales/fr.yml b/config/locales/fr.yml
index 8272980ff..f9f16fcee 100644
--- a/config/locales/fr.yml
+++ b/config/locales/fr.yml
@@ -426,11 +426,6 @@ fr:
         archived_dossier: "Votre dossier sera conservé %{duree_conservation_dossiers_dans_ds} mois supplémentaire"
         identite:
           legend: 'Ce dossier est : '
-          self_title: Votre identité
-          callout_text: Vous agissez en tant que mandataire, soit professionnellement (comme expert-comptable, avocat, agent public…) soit personnellement (famille). Assurez-vous de respecter les conditions
-          callout_link: des Articles 1984 et suivants du Code civil.
-          callout_link_title: Articles 1984 et suivants du Code civil
-          beneficiaire_title: Identité du bénéficiaire
           identity_siret: Identifier votre établissement
           civility: Civilité
           first_name: Prénom
diff --git a/config/locales/models/procedure/en.yml b/config/locales/models/procedure/en.yml
index 19aca8bdf..2f1d1c8b8 100644
--- a/config/locales/models/procedure/en.yml
+++ b/config/locales/models/procedure/en.yml
@@ -37,6 +37,7 @@ en:
         lien_dpo: Link or email to contact the data protection officer (DPO)
         duree_conservation_dossiers_dans_ds: Duration files will be kept
         max_duree_conservation_dossiers_dans_ds: Max duration allowed to keep files
+        for_tiers_enabled: Enable a third party to submit a file
         aasm_state:
           brouillon: Draft
           publiee: Published
diff --git a/config/locales/models/procedure/fr.yml b/config/locales/models/procedure/fr.yml
index cdf2309b8..78e2bcf26 100644
--- a/config/locales/models/procedure/fr.yml
+++ b/config/locales/models/procedure/fr.yml
@@ -20,6 +20,7 @@ fr:
         organisation: Organisme
         duree_conservation_dossiers_dans_ds: Durée de conservation des dossiers
         max_duree_conservation_dossiers_dans_ds: Durée maximale de conservation des dossiers (autorisée par un super admin)
+        for_tiers_enabled: Activer le dépot par un tiers
         id: Id
         libelle: Titre de la démarche
         description: Quel est l’objet de la démarche ?
diff --git a/config/routes.rb b/config/routes.rb
index caf5a3358..9256e08a2 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -361,6 +361,7 @@ Rails.application.routes.draw do
     resources :dossiers, only: [:index, :show, :destroy, :new] do
       member do
         get 'identite'
+        patch 'identite'
         patch 'update_identite'
         post 'clone'
         get 'siret'
diff --git a/db/migrate/20240417053843_add_column_for_tiers_enabled_to_procedure.rb b/db/migrate/20240417053843_add_column_for_tiers_enabled_to_procedure.rb
new file mode 100644
index 000000000..c2e40a0d4
--- /dev/null
+++ b/db/migrate/20240417053843_add_column_for_tiers_enabled_to_procedure.rb
@@ -0,0 +1,5 @@
+class AddColumnForTiersEnabledToProcedure < ActiveRecord::Migration[7.0]
+  def change
+    add_column :procedures, :for_tiers_enabled, :boolean, default: true, null: false
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index 1caaf322c..b936bf6b3 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[7.0].define(version: 2024_04_16_062900) do
+ActiveRecord::Schema[7.0].define(version: 2024_04_17_053843) do
   # These are extensions that must be enabled in order to support this database
   enable_extension "pg_buffercache"
   enable_extension "pg_stat_statements"
@@ -894,6 +894,7 @@ ActiveRecord::Schema[7.0].define(version: 2024_04_16_062900) do
     t.boolean "euro_flag", default: false
     t.boolean "experts_require_administrateur_invitation", default: false
     t.boolean "for_individual", default: false
+    t.boolean "for_tiers_enabled", default: true, null: false
     t.datetime "hidden_at", precision: nil
     t.datetime "hidden_at_as_template", precision: nil
     t.boolean "instructeurs_self_management_enabled", default: false
diff --git a/spec/support/shared_examples_for_prefilled_dossier.rb b/spec/support/shared_examples_for_prefilled_dossier.rb
index 4a31f3668..3ed07a18b 100644
--- a/spec/support/shared_examples_for_prefilled_dossier.rb
+++ b/spec/support/shared_examples_for_prefilled_dossier.rb
@@ -8,7 +8,9 @@ shared_examples "the user has got a prefilled dossier, owned by themselves" do
       expect(page).to have_field('Prénom', with: prenom_value)
       expect(page).to have_field('Nom', with: nom_value)
     end
-    click_on 'Continuer'
+    within "#identite-form" do
+      click_on 'Continuer'
+    end
 
     expect(page).to have_current_path(brouillon_dossier_path(dossier))
     expect(page).to have_field(type_de_champ_text.libelle, with: text_value)
diff --git a/spec/system/accessibilite/wcag_usager_spec.rb b/spec/system/accessibilite/wcag_usager_spec.rb
index a262774c5..d8ad6fd10 100644
--- a/spec/system/accessibilite/wcag_usager_spec.rb
+++ b/spec/system/accessibilite/wcag_usager_spec.rb
@@ -126,7 +126,9 @@ describe 'wcag rules for usager', js: true do
         fill_in('Prénom', with: 'prenom')
         fill_in('Nom', with: 'nom')
       end
-      click_on 'Continuer'
+      within "#identite-form" do
+        click_on 'Continuer'
+      end
 
       expect(page).to be_axe_clean
     end
diff --git a/spec/system/api_particulier/api_particulier_spec.rb b/spec/system/api_particulier/api_particulier_spec.rb
index ecd9a1982..aa06327db 100644
--- a/spec/system/api_particulier/api_particulier_spec.rb
+++ b/spec/system/api_particulier/api_particulier_spec.rb
@@ -272,7 +272,9 @@ describe 'fetch API Particulier Data', js: true do
           fill_in('Nom', with: 'nom')
         end
 
-        click_button('Continuer')
+        within "#identite-form" do
+          click_on 'Continuer'
+        end
 
         fill_in 'Le numéro d’allocataire CAF', with: numero_allocataire
         fill_in 'Le code postal', with: 'wrong_code'
@@ -331,7 +333,9 @@ describe 'fetch API Particulier Data', js: true do
           fill_in('Prénom', with: 'Georges')
           fill_in('Nom', with: 'Moustaki')
         end
-        click_button('Continuer')
+        within "#identite-form" do
+          click_on 'Continuer'
+        end
 
         fill_in "Identifiant", with: 'wrong code'
 
@@ -405,7 +409,9 @@ describe 'fetch API Particulier Data', js: true do
           fill_in('Prénom', with: 'Angela Claire Louise')
           fill_in('Nom', with: 'Dubois')
         end
-        click_button('Continuer')
+        within "#identite-form" do
+          click_on 'Continuer'
+        end
 
         fill_in "INE", with: 'wrong code'
 
@@ -469,7 +475,9 @@ describe 'fetch API Particulier Data', js: true do
           fill_in('Prénom', with: 'Karine')
           fill_in('Nom', with: 'FERRI')
         end
-        click_button('Continuer')
+        within "#identite-form" do
+          click_on 'Continuer'
+        end
 
         fill_in 'Le numéro fiscal', with: numero_fiscal
         fill_in "La référence d’avis d’imposition", with: 'wrong_code'
diff --git a/spec/system/routing/rules_full_scenario_spec.rb b/spec/system/routing/rules_full_scenario_spec.rb
index 4163ca067..8a94b15b4 100644
--- a/spec/system/routing/rules_full_scenario_spec.rb
+++ b/spec/system/routing/rules_full_scenario_spec.rb
@@ -258,7 +258,9 @@ describe 'The routing with rules', js: true do
     find('label', text: 'Monsieur').click
     fill_in('Prénom', with: 'prenom', visible: true)
     fill_in('Nom', with: 'Nom', visible: true)
-    click_button('Continuer')
+    within "#identite-form" do
+      click_button('Continuer')
+    end
 
     # the old system should not be present
     expect(page).not_to have_selector("#dossier_groupe_instructeur_id")
diff --git a/spec/system/users/brouillon_spec.rb b/spec/system/users/brouillon_spec.rb
index cd20a584b..97498b83b 100644
--- a/spec/system/users/brouillon_spec.rb
+++ b/spec/system/users/brouillon_spec.rb
@@ -665,7 +665,9 @@ describe 'The user' do
     find('label', text: 'Monsieur').click
     fill_in('Prénom', with: 'prenom', visible: true)
     fill_in('Nom', with: 'Nom', visible: true)
-    click_on 'Continuer'
+    within "#identite-form" do
+      click_on 'Continuer'
+    end
     expect(page).to have_current_path(brouillon_dossier_path(user_dossier))
   end
 end
diff --git a/spec/system/users/dossier_creation_spec.rb b/spec/system/users/dossier_creation_spec.rb
index 531b0735d..a930672cd 100644
--- a/spec/system/users/dossier_creation_spec.rb
+++ b/spec/system/users/dossier_creation_spec.rb
@@ -28,7 +28,9 @@ describe 'Creating a new dossier:', js: true do
 
       shared_examples 'the user can create a new draft' do
         it do
-          click_button('Continuer')
+          within "#identite-form" do
+            click_button('Continuer')
+          end
 
           expect(page).to have_current_path(brouillon_dossier_path(procedure.dossiers.last))
           expect(user.dossiers.first.individual.birthdate).to eq(expected_birthday)
@@ -58,7 +60,6 @@ describe 'Creating a new dossier:', js: true do
       context 'when individual fill dossier for a tiers' do
         it 'completes the form with email notification method selected' do
           find('label', text: 'Pour un bénéficiaire : membre de la famille, proche, mandant, professionnel en charge du suivi du dossier…').click
-
           within('.mandataire-infos') do
             fill_in('Prénom', with: 'John')
             fill_in('Nom', with: 'Doe')
@@ -73,7 +74,15 @@ describe 'Creating a new dossier:', js: true do
 
           find('label', text: 'Par e-mail').click
           fill_in('dossier_individual_attributes_email', with: 'prenom.nom@mail.com')
-          click_button('Continuer')
+          find('label', text: 'Monsieur').click # force focus out
+          within "#identite-form" do
+            within '.suspect-email' do
+              expect(page).to have_content("Information : Voulez-vous dire ?")
+              click_button("Oui")
+            end
+            click_button("Continuer")
+          end
+
           expect(procedure.dossiers.last.individual.notification_method == 'email')
           expect(page).to have_current_path(brouillon_dossier_path(procedure.dossiers.last))
         end
@@ -93,7 +102,10 @@ describe 'Creating a new dossier:', js: true do
           end
 
           find('label', text: 'Pas de notification').click
-          click_button('Continuer')
+          within "#identite-form" do
+            click_button('Continuer')
+          end
+
           expect(procedure.dossiers.last.individual.notification_method.empty?)
           expect(page).to have_current_path(brouillon_dossier_path(procedure.dossiers.last))
         end
diff --git a/spec/system/users/dropdown_spec.rb b/spec/system/users/dropdown_spec.rb
index 25645c02e..987570962 100644
--- a/spec/system/users/dropdown_spec.rb
+++ b/spec/system/users/dropdown_spec.rb
@@ -79,7 +79,9 @@ describe 'dropdown list with other option activated', js: true do
       fill_in('Prénom', with: 'prenom')
       fill_in('Nom', with: 'nom')
     end
-    click_on 'Continuer'
+    within "#identite-form" do
+      click_on 'Continuer'
+    end
     expect(page).to have_current_path(brouillon_dossier_path(user_dossier))
   end
 end
diff --git a/spec/system/users/linked_dropdown_spec.rb b/spec/system/users/linked_dropdown_spec.rb
index 83b8fd459..c6f3b7cac 100644
--- a/spec/system/users/linked_dropdown_spec.rb
+++ b/spec/system/users/linked_dropdown_spec.rb
@@ -85,7 +85,9 @@ describe 'linked dropdown lists' do
       fill_in('Prénom', with: 'prenom')
       fill_in('Nom', with: 'nom')
     end
-    click_on 'Continuer'
+    within "#identite-form" do
+      click_on 'Continuer'
+    end
     expect(page).to have_current_path(brouillon_dossier_path(user_dossier))
   end
 end
diff --git a/spec/views/users/dossiers/identite.html.haml_spec.rb b/spec/views/users/dossiers/identite.html.haml_spec.rb
index 7c065f980..0ca066eee 100644
--- a/spec/views/users/dossiers/identite.html.haml_spec.rb
+++ b/spec/views/users/dossiers/identite.html.haml_spec.rb
@@ -1,5 +1,4 @@
 describe 'users/dossiers/identite', type: :view do
-  let(:procedure) { create(:simple_procedure, :for_individual) }
   let(:dossier) { create(:dossier, :with_service, state: Dossier.states.fetch(:brouillon), procedure: procedure) }
 
   before do
@@ -9,18 +8,43 @@ describe 'users/dossiers/identite', type: :view do
 
   subject! { render }
 
-  it 'has identity fields' do
-    within('.individual-infos') do
-      expect(rendered).to have_field(id: 'Prenom')
-      expect(rendered).to have_field(id: 'Nom')
+  context 'when procedure has for_tiers_enabled' do
+    let(:procedure) { create(:simple_procedure, :for_individual) }
+
+    it 'has choice for you or a tiers' do
+      expect(rendered).to have_content "Pour vous"
+      expect(rendered).to have_content "Pour un bénéficiaire : membre de la famille, proche, mandant, professionnel en charge du suivi du dossier…"
+    end
+
+    it 'has identity fields' do
+      within('.individual-infos') do
+        expect(rendered).to have_field(id: 'Prenom')
+        expect(rendered).to have_field(id: 'Nom')
+      end
+    end
+
+    context 'when the demarche asks for the birthdate' do
+      let(:procedure) { create(:simple_procedure, for_individual: true, ask_birthday: true) }
+
+      it 'has a birthday field' do
+        expect(rendered).to have_field('Date de naissance')
+      end
     end
   end
 
-  context 'when the demarche asks for the birthdate' do
-    let(:procedure) { create(:simple_procedure, for_individual: true, ask_birthday: true) }
+  context 'when procedure has for_tiers_enabled' do
+    let(:procedure) { create(:simple_procedure, :for_individual, for_tiers_enabled: false) }
 
-    it 'has a birthday field' do
-      expect(rendered).to have_field('Date de naissance')
+    it 'has choice for you or a tiers' do
+      expect(rendered).not_to have_content "Pour vous"
+      expect(rendered).not_to have_content "Pour un bénéficiaire : membre de la famille, proche, mandant, professionnel en charge du suivi du dossier…"
+    end
+
+    it 'has identity fields' do
+      within('.individual-infos') do
+        expect(rendered).to have_field(id: 'Prenom')
+        expect(rendered).to have_field(id: 'Nom')
+      end
     end
   end
 end