diff --git a/app/assets/stylesheets/attachment.scss b/app/assets/stylesheets/attachment.scss
index 2584c972e..3688742e7 100644
--- a/app/assets/stylesheets/attachment.scss
+++ b/app/assets/stylesheets/attachment.scss
@@ -25,7 +25,8 @@
   }
 }
 
-.attachment-multiple:not(.fr-downloads-group) {
+.attachment-multiple:not(.fr-downloads-group),
+.attachment-multiple.fr-downloads-group[data-controller=replace-attachment] {
   ul {
     list-style-type: none;
     padding-inline-start: 0;
@@ -42,6 +43,10 @@
     position: relative;
     top: -1rem;
   }
+
+  .fr-btn {
+    align-self: flex-start;
+  }
 }
 
 .attachment-multiple.fr-downloads-group.destroyable {
diff --git a/app/components/attachment/edit_component.rb b/app/components/attachment/edit_component.rb
index 7abb27f93..3cd253b22 100644
--- a/app/components/attachment/edit_component.rb
+++ b/app/components/attachment/edit_component.rb
@@ -4,12 +4,14 @@ class Attachment::EditComponent < ApplicationComponent
   attr_reader :attachment
   attr_reader :user_can_destroy
   alias user_can_destroy? user_can_destroy
+  attr_reader :user_can_replace
+  alias user_can_replace? user_can_replace
   attr_reader :as_multiple
   alias as_multiple? as_multiple
 
   EXTENSIONS_ORDER = ['jpeg', 'png', 'pdf', 'zip'].freeze
 
-  def initialize(champ: nil, auto_attach_url: nil, attached_file:, direct_upload: true, index: 0, as_multiple: false, view_as: :link, user_can_destroy: true, **kwargs)
+  def initialize(champ: nil, auto_attach_url: nil, attached_file:, direct_upload: true, index: 0, as_multiple: false, view_as: :link, user_can_destroy: true, user_can_replace: false, **kwargs)
     @as_multiple = as_multiple
     @attached_file = attached_file
     @auto_attach_url = auto_attach_url
@@ -18,6 +20,7 @@ class Attachment::EditComponent < ApplicationComponent
     @index = index
     @view_as = view_as
     @user_can_destroy = user_can_destroy
+    @user_can_replace = user_can_replace
 
     # attachment passed by kwarg because we don't want a default (nil) value.
     @attachment = if kwargs.key?(:attachment)
@@ -64,13 +67,14 @@ class Attachment::EditComponent < ApplicationComponent
   def file_field_options
     track_issue_with_missing_validators if missing_validators?
     {
-      class: "fr-upload attachment-input #{attachment_input_class} #{persisted? ? 'hidden' : ''}",
+      class: class_names("fr-upload attachment-input": true, "#{attachment_input_class}": true, "hidden": persisted?, "fr-mt-2w": user_can_replace?),
       direct_upload: @direct_upload,
       id: input_id,
       aria: { describedby: champ&.describedby_id },
       data: {
         auto_attach_url:
       }.merge(has_file_size_validator? ? { max_file_size: } : {})
+        .merge(user_can_replace? ? { replace_attachment_target: "input" } : {})
     }.merge(has_content_type_validator? ? { accept: accept_content_type } : {})
   end
 
@@ -103,6 +107,24 @@ class Attachment::EditComponent < ApplicationComponent
     }
   end
 
+  def replace_button_options
+    {
+      type: 'button',
+      data: {
+        action: "click->replace-attachment#open",
+        auto_attach_url: auto_attach_url
+      }.compact
+    }
+  end
+
+  def replace_controller_attributes
+    return {} if !persisted? || !user_can_replace? || as_multiple?
+
+    {
+      "data-controller": 'replace-attachment'
+    }
+  end
+
   def retry_button_options
     {
       type: 'button',
@@ -155,7 +177,9 @@ class Attachment::EditComponent < ApplicationComponent
   def auto_attach_url
     return @auto_attach_url if @auto_attach_url.present?
 
-    return helpers.auto_attach_url(@champ) if @champ.present?
+    params = { replace_attachment_id: @attachment.id } if user_can_replace? && @attachment.present?
+
+    return helpers.auto_attach_url(@champ, params) if @champ.present?
 
     nil
   end
diff --git a/app/components/attachment/edit_component/edit_component.en.yml b/app/components/attachment/edit_component/edit_component.en.yml
index 33148c1be..7e2a20625 100644
--- a/app/components/attachment/edit_component/edit_component.en.yml
+++ b/app/components/attachment/edit_component/edit_component.en.yml
@@ -4,6 +4,9 @@ en:
   allowed_formats: "Supported formats : %{formats}"
   retry: Retry
   delete: Delete
+  delete_file: Delete file %{filename}
+  replace: Replace
+  replace_file: Replace file %{filename}
   errors:
     uploading: "An error occurred while sending the file."
     virus_infected: "Virus detected, please send another file."
diff --git a/app/components/attachment/edit_component/edit_component.fr.yml b/app/components/attachment/edit_component/edit_component.fr.yml
index fa4e86141..19ba08a3a 100644
--- a/app/components/attachment/edit_component/edit_component.fr.yml
+++ b/app/components/attachment/edit_component/edit_component.fr.yml
@@ -4,6 +4,9 @@ fr:
   allowed_formats: "Formats supportés : %{formats}"
   retry: Réessayer
   delete: Supprimer
+  delete_file: Supprimer le fichier %{filename}
+  replace: Remplacer
+  replace_file: Remplacer le fichier %{filename}
   errors:
     uploading: "Une erreur s’est produite pendant l’envoi du fichier."
     virus_infected: "Virus détecté, merci d’envoyer un autre fichier."
diff --git a/app/components/attachment/edit_component/edit_component.html.haml b/app/components/attachment/edit_component/edit_component.html.haml
index 90ddb9512..bc54ef9f4 100644
--- a/app/components/attachment/edit_component/edit_component.html.haml
+++ b/app/components/attachment/edit_component/edit_component.html.haml
@@ -1,14 +1,16 @@
-.attachment.fr-upload-group{ { id: attachment ? dom_id(attachment, :edit) : nil, class: class_names("fr-mb-2w": !(as_multiple? && downloadable?)) }.compact }
+.attachment.fr-upload-group{ { id: attachment ? dom_id(attachment, :edit) : nil, class: class_names("fr-mb-2w": !(as_multiple? && downloadable?)) }.compact, **replace_controller_attributes }
   - if persisted?
     %div{ id: dom_id(attachment, :persisted_row) }
       .flex.flex-gap-2{ class: class_names("attachment-error": attachment.virus_scanner_error?) }
         - if user_can_destroy?
-          = link_to(t('.delete'), destroy_attachment_path, **remove_button_options, class: "fr-btn fr-btn--tertiary fr-btn--sm fr-icon-delete-line", title: "Supprimer le fichier #{attachment.filename}")
+          = link_to(t('.delete'), destroy_attachment_path, **remove_button_options, class: "fr-btn fr-btn--tertiary fr-btn--sm fr-icon-delete-line", title: t(".delete_file", filename: attachment.filename))
+        - elsif user_can_replace?
+          = button_tag t('.replace'), **replace_button_options, class: "fr-btn fr-btn--tertiary fr-btn--sm", title: t(".replace_file", filename: attachment.filename)
 
-        .fr-py-1v
-          - if downloadable?
-            = render Dsfr::DownloadComponent.new(attachment:)
-          - else
+        - if downloadable?
+          = render Dsfr::DownloadComponent.new(attachment:)
+        - else
+          .fr-py-1v
             %span.attachment-filename.fr-mr-1w= link_to_if(viewable?, attachment.filename.to_s, helpers.url_for(attachment.blob), title: "Ouvrir le fichier #{attachment.filename.to_s}", **helpers.external_link_attributes)
 
           = render Attachment::ProgressComponent.new(attachment: attachment)
diff --git a/app/components/attachment/multiple_component.rb b/app/components/attachment/multiple_component.rb
index c0229bf90..2a1baa3d7 100644
--- a/app/components/attachment/multiple_component.rb
+++ b/app/components/attachment/multiple_component.rb
@@ -12,15 +12,18 @@ class Attachment::MultipleComponent < ApplicationComponent
   attr_reader :view_as
   attr_reader :user_can_destroy
   alias user_can_destroy? user_can_destroy
+  attr_reader :user_can_replace
+  alias user_can_replace? user_can_replace
 
   delegate :count, :empty?, to: :attachments, prefix: true
 
-  def initialize(champ:, attached_file:, form_object_name: nil, view_as: :link, user_can_destroy: true, max: nil)
+  def initialize(champ:, attached_file:, form_object_name: nil, view_as: :link, user_can_destroy: true, user_can_replace: false, max: nil)
     @champ = champ
     @attached_file = attached_file
     @form_object_name = form_object_name
     @view_as = view_as
     @user_can_destroy = user_can_destroy
+    @user_can_replace = user_can_replace
     @max = max || DEFAULT_MAX_ATTACHMENTS
 
     @attachments = attached_file.attachments || []
@@ -48,4 +51,12 @@ class Attachment::MultipleComponent < ApplicationComponent
 
     nil
   end
+
+  def replace_controller_attributes
+    return {} unless user_can_replace?
+
+    {
+      "data-controller": 'replace-attachment'
+    }
+  end
 end
diff --git a/app/components/attachment/multiple_component/multiple_component.html.haml b/app/components/attachment/multiple_component/multiple_component.html.haml
index b7a9036e8..ecca7269f 100644
--- a/app/components/attachment/multiple_component/multiple_component.html.haml
+++ b/app/components/attachment/multiple_component/multiple_component.html.haml
@@ -1,13 +1,13 @@
-.fr-mb-4w.attachment-multiple{ class: class_names("fr-downloads-group": view_as == :download, "destroyable": user_can_destroy?) }
+.fr-mb-4w.attachment-multiple{ class: class_names("fr-downloads-group": view_as == :download, "destroyable": user_can_destroy?), **replace_controller_attributes }
   = template
 
   %ul
     - each_attachment do |attachment, index|
       %li{ id: dom_id(attachment) }
-        = render Attachment::EditComponent.new(champ:, attached_file:, attachment:, index:, as_multiple: true, view_as:, user_can_destroy:, form_object_name:)
+        = render Attachment::EditComponent.new(champ:, attached_file:, attachment:, index:, as_multiple: true, view_as:, user_can_destroy:, user_can_replace:, form_object_name:)
 
   %div{ id: empty_component_id, class: class_names("hidden": !can_attach_next?) }
-    = render Attachment::EditComponent.new(champ:, attached_file:, attachment: nil, index: attachments_count, user_can_destroy:, form_object_name:)
+    = render Attachment::EditComponent.new(champ:, attached_file:, attachment: nil, index: attachments_count, user_can_destroy:, user_can_replace:, form_object_name:)
 
   // single poll and refresh message for all attachments
   = render Attachment::PendingPollComponent.new(attachments: attachments, poll_url:, context: poll_context)
diff --git a/app/components/editable_champ/piece_justificative_component.rb b/app/components/editable_champ/piece_justificative_component.rb
index 9a14d389f..3d1cfaf80 100644
--- a/app/components/editable_champ/piece_justificative_component.rb
+++ b/app/components/editable_champ/piece_justificative_component.rb
@@ -11,6 +11,10 @@ class EditableChamp::PieceJustificativeComponent < EditableChamp::EditableChampB
     !@champ.mandatory? || @champ.dossier.brouillon?
   end
 
+  def user_can_replace?
+    @champ.mandatory? && @champ.dossier.en_construction?
+  end
+
   def max
     [true, nil].include?(@champ.procedure&.piece_justificative_multiple?) ? Attachment::MultipleComponent::DEFAULT_MAX_ATTACHMENTS : 1
   end
diff --git a/app/components/editable_champ/piece_justificative_component/piece_justificative_component.html.haml b/app/components/editable_champ/piece_justificative_component/piece_justificative_component.html.haml
index 4d549cb22..322c029aa 100644
--- a/app/components/editable_champ/piece_justificative_component/piece_justificative_component.html.haml
+++ b/app/components/editable_champ/piece_justificative_component/piece_justificative_component.html.haml
@@ -1,4 +1,4 @@
-= render Attachment::MultipleComponent.new(champ: @champ, attached_file: @champ.piece_justificative_file, form_object_name: @form.object_name, view_as:, user_can_destroy: user_can_destroy?, max:) do |c|
+= render Attachment::MultipleComponent.new(champ: @champ, attached_file: @champ.piece_justificative_file, form_object_name: @form.object_name, view_as:, user_can_destroy: user_can_destroy?, user_can_replace: user_can_replace?, max:) do |c|
   - if @champ.type_de_champ.piece_justificative_template&.attached?
     - c.with_template do
       = render partial: "shared/piece_justificative_template", locals: { champ: @champ }
diff --git a/app/components/editable_champ/titre_identite_component.rb b/app/components/editable_champ/titre_identite_component.rb
index 7bb8536d0..cde3489ad 100644
--- a/app/components/editable_champ/titre_identite_component.rb
+++ b/app/components/editable_champ/titre_identite_component.rb
@@ -1,2 +1,9 @@
 class EditableChamp::TitreIdentiteComponent < EditableChamp::EditableChampBaseComponent
+  def user_can_destroy?
+    !@champ.mandatory? || @champ.dossier.brouillon?
+  end
+
+  def user_can_replace?
+    @champ.mandatory? && @champ.dossier.en_construction?
+  end
 end
diff --git a/app/components/editable_champ/titre_identite_component/titre_identite_component.html.haml b/app/components/editable_champ/titre_identite_component/titre_identite_component.html.haml
index 1a56c074d..778ce957c 100644
--- a/app/components/editable_champ/titre_identite_component/titre_identite_component.html.haml
+++ b/app/components/editable_champ/titre_identite_component/titre_identite_component.html.haml
@@ -1,5 +1,5 @@
-- user_can_destroy = !@champ.mandatory? || @champ.dossier.brouillon?
 
 - if @champ.type_de_champ.piece_justificative_template&.attached?
   = render partial: "shared/piece_justificative_template", locals: { champ: @champ }
-= render Attachment::EditComponent.new(champ: @form.object, attached_file: @champ.piece_justificative_file, attachment: @champ.piece_justificative_file[0], form_object_name: @form.object_name, user_can_destroy:)
+= render Attachment::EditComponent.new(champ: @form.object, attached_file: @champ.piece_justificative_file, attachment: @champ.piece_justificative_file[0], form_object_name: @form.object_name,
+  user_can_destroy: user_can_destroy?, user_can_replace: user_can_replace?)
diff --git a/app/controllers/champs/piece_justificative_controller.rb b/app/controllers/champs/piece_justificative_controller.rb
index f95968b62..92e776370 100644
--- a/app/controllers/champs/piece_justificative_controller.rb
+++ b/app/controllers/champs/piece_justificative_controller.rb
@@ -28,9 +28,22 @@ class Champs::PieceJustificativeController < ApplicationController
   end
 
   def attach_piece_justificative
-    @champ.piece_justificative_file.attach(params[:blob_signed_id])
-    save_succeed = @champ.save
+    save_succeed = nil
+
+    ActiveStorage::Attachment.transaction do
+      if params.key?(:replace_attachment_id)
+        @champ.piece_justificative_file.attachments.find do
+          _1.id == params[:replace_attachment_id].to_i
+        end&.destroy
+      end
+
+      @champ.piece_justificative_file.attach(params[:blob_signed_id])
+
+      save_succeed = @champ.save
+    end
+
     @champ.dossier.update(last_champ_updated_at: Time.zone.now.utc) if save_succeed
+
     save_succeed
   end
 
diff --git a/app/helpers/champ_helper.rb b/app/helpers/champ_helper.rb
index 4368730c7..2e7971a85 100644
--- a/app/helpers/champ_helper.rb
+++ b/app/helpers/champ_helper.rb
@@ -7,11 +7,11 @@ module ChampHelper
     simple_format(auto_linked_text, {}, sanitize: false)
   end
 
-  def auto_attach_url(object)
+  def auto_attach_url(object, params = {})
     if object.is_a?(Champ)
-      champs_attach_piece_justificative_url(object.id)
+      champs_attach_piece_justificative_url(object.id, params)
     elsif object.is_a?(TypeDeChamp)
-      piece_justificative_template_admin_procedure_type_de_champ_url(stable_id: object.stable_id, procedure_id: object.procedure.id)
+      piece_justificative_template_admin_procedure_type_de_champ_url(stable_id: object.stable_id, procedure_id: object.procedure.id, **params)
     end
   end
 end
diff --git a/app/javascript/controllers/replace_attachment_controller.ts b/app/javascript/controllers/replace_attachment_controller.ts
new file mode 100644
index 000000000..07dda54f4
--- /dev/null
+++ b/app/javascript/controllers/replace_attachment_controller.ts
@@ -0,0 +1,30 @@
+import { ApplicationController } from './application_controller';
+import { show } from '@utils';
+
+export class ReplaceAttachmentController extends ApplicationController {
+  static targets = ['input'];
+
+  declare readonly inputTarget: HTMLInputElement;
+
+  open(event: Event) {
+    show(this.inputTarget);
+    this.inputTarget.click(); // opens input prompt
+
+    const target = event.currentTarget as HTMLButtonElement;
+
+    if (target.dataset.autoAttachUrl) {
+      // set the auto attach url specific to this button to replace the related attachment
+      this.inputTarget.dataset.originalAutoAttachUrl =
+        this.inputTarget.dataset.autoAttachUrl;
+
+      this.inputTarget.dataset.autoAttachUrl = target.dataset.autoAttachUrl;
+
+      // reset autoAttachUrl which would add an attachment
+      // when replace is not finalized
+      this.inputTarget.addEventListener('cancel', () => {
+        this.inputTarget.dataset.autoAttachUrl =
+          this.inputTarget.dataset.originalAutoAttachUrl;
+      });
+    }
+  }
+}
diff --git a/spec/components/attachment/multiple_component_spec.rb b/spec/components/attachment/multiple_component_spec.rb
index b34ab17cb..2ac7396be 100644
--- a/spec/components/attachment/multiple_component_spec.rb
+++ b/spec/components/attachment/multiple_component_spec.rb
@@ -38,13 +38,7 @@ RSpec.describe Attachment::MultipleComponent, type: :component do
 
   context 'when there is an attachment' do
     before do
-      attached_file.attach(
-        io: StringIO.new("x" * 2),
-        filename: "me.jpg",
-        content_type: "image/jpeg",
-        metadata: { virus_scan_result: ActiveStorage::VirusScanner::SAFE }
-      )
-      champ.save!
+      attach_to_champ(attached_file, champ)
     end
 
     it 'renders the filenames' do
@@ -98,4 +92,26 @@ RSpec.describe Attachment::MultipleComponent, type: :component do
       expect(subject).to have_selector('[data-controller=turbo-poll]')
     end
   end
+
+  context 'when user can replace' do
+    let(:kwargs) { { user_can_replace: true } }
+
+    before do
+      attach_to_champ(attached_file, champ)
+    end
+
+    it 'setup controller' do
+      expect(subject).to have_selector('[data-controller=replace-attachment]').once
+    end
+  end
+
+  def attach_to_champ(attached_file, champ)
+    attached_file.attach(
+      io: StringIO.new("x" * 2),
+      filename: "me.jpg",
+      content_type: "image/jpeg",
+      metadata: { virus_scan_result: ActiveStorage::VirusScanner::SAFE }
+    )
+    champ.save!
+  end
 end
diff --git a/spec/controllers/champs/piece_justificative_controller_spec.rb b/spec/controllers/champs/piece_justificative_controller_spec.rb
index 6deb1e060..ac09d58d6 100644
--- a/spec/controllers/champs/piece_justificative_controller_spec.rb
+++ b/spec/controllers/champs/piece_justificative_controller_spec.rb
@@ -5,6 +5,8 @@ describe Champs::PieceJustificativeController, type: :controller do
   let(:champ) { dossier.champs_public.first }
 
   describe '#update' do
+    let(:replace_attachment_id) { nil }
+
     render_views
     before { sign_in user }
 
@@ -12,8 +14,9 @@ describe Champs::PieceJustificativeController, type: :controller do
       put :update, params: {
         position: '1',
         champ_id: champ.id,
-        blob_signed_id: file
-      }, format: :turbo_stream
+        blob_signed_id: file,
+        replace_attachment_id:
+      }.compact, format: :turbo_stream
     end
 
     context 'when the file is valid' do
@@ -65,6 +68,33 @@ describe Champs::PieceJustificativeController, type: :controller do
         expect(JSON.parse(response.body)).to eq({ 'errors' => ['La pièce justificative n’est pas d’un type accepté'] })
       end
     end
+
+    context 'replace an attachment' do
+      let(:file) { fixture_file_upload('spec/fixtures/files/piece_justificative_0.pdf', 'application/pdf') }
+      before { subject }
+
+      context "attachment associated to dossier" do
+        let(:champ) { create(:champ, :with_piece_justificative_file, dossier:) }
+        let(:replace_attachment_id) { champ.piece_justificative_file.first.id }
+
+        it "replaces an existing attachment" do
+          champ.reload
+
+          expect(champ.piece_justificative_file.attachments.count).to eq(1)
+          expect(champ.piece_justificative_file.attachments.first.filename).to eq("piece_justificative_0.pdf")
+        end
+      end
+
+      context "attachment not associated to dossier" do
+        let(:other_champ) { create(:champ, :with_piece_justificative_file) }
+        let(:replace_attachment_id) { other_champ.piece_justificative_file.first.id }
+
+        it "add attachment, don't replace attachment" do
+          expect(champ.reload.piece_justificative_file.attachments.count).to eq(1)
+          expect(other_champ.reload.piece_justificative_file.attachments.count).to eq(1)
+        end
+      end
+    end
   end
 
   describe '#template' do
diff --git a/spec/system/users/en_construction_spec.rb b/spec/system/users/en_construction_spec.rb
new file mode 100644
index 000000000..51d3ded7c
--- /dev/null
+++ b/spec/system/users/en_construction_spec.rb
@@ -0,0 +1,77 @@
+describe "Dossier en_construction" do
+  let(:user) { create(:user) }
+  let(:procedure) { create(:simple_procedure, :with_piece_justificative, :with_titre_identite) }
+  let(:dossier) { create(:dossier, :en_construction, :with_individual, :with_populated_champs, user:, procedure:) }
+
+  let(:tdc) {
+    procedure.active_revision.types_de_champ_public.find { _1.type_champ == "piece_justificative" }
+  }
+
+  let(:champ) {
+    dossier.champs_public.find { _1.type_de_champ_id == tdc.id }
+  }
+
+  scenario 'delete a non mandatory piece justificative', js: true do
+    visit_dossier(dossier)
+
+    expect(page).not_to have_button("Remplacer")
+    click_on "Supprimer le fichier toto.txt"
+
+    expect(page).not_to have_text("toto.txt")
+  end
+
+  context "with a mandatory piece justificative" do
+    before do
+      tdc.update_attribute(:mandatory, true)
+    end
+
+    scenario 'remplace a mandatory piece justificative', js: true do
+      visit_dossier(dossier)
+
+      click_on "Remplacer le fichier toto.txt"
+
+      input_selector = "#attachment-multiple-empty-#{champ.id}"
+      expect(page).to have_selector(input_selector)
+      find(input_selector).attach_file(Rails.root.join('spec/fixtures/files/file.pdf'))
+
+      expect(page).to have_text("file.pdf")
+      expect(page).not_to have_text("toto.txt")
+    end
+  end
+
+  context "with a mandatory titre identite" do
+    let(:tdc) {
+      procedure.active_revision.types_de_champ_public.find { _1.type_champ == "titre_identite" }
+    }
+
+    before do
+      tdc.update_attribute(:mandatory, true)
+    end
+
+    scenario 'remplace a mandatory titre identite', js: true do
+      visit_dossier(dossier)
+
+      click_on "Remplacer le fichier toto.png"
+
+      input_selector = ".attachment-input-#{champ.piece_justificative_file.attachments.first.id}"
+      expect(page).to have_selector(input_selector)
+      find(input_selector).attach_file(Rails.root.join('spec/fixtures/files/file.pdf'))
+
+      expect(page).to have_text("file.pdf")
+      expect(page).not_to have_text("toto.png")
+    end
+  end
+
+  private
+
+  def visit_dossier(dossier)
+    visit modifier_dossier_path(dossier)
+
+    expect(page).to have_current_path(new_user_session_path)
+    fill_in 'user_email', with: user.email
+    fill_in 'user_password', with: user.password
+    click_on 'Se connecter'
+
+    expect(page).to have_current_path(modifier_dossier_path(dossier))
+  end
+end