diff --git a/app/assets/stylesheets/new_design/help_dropdown.scss b/app/assets/stylesheets/new_design/help_dropdown.scss
new file mode 100644
index 000000000..01d8bd70c
--- /dev/null
+++ b/app/assets/stylesheets/new_design/help_dropdown.scss
@@ -0,0 +1,51 @@
+@import "colors";
+@import "constants";
+
+.help-dropdown {
+  .dropdown-content {
+    width: 340px;
+  }
+
+  .dropdown-description {
+    font-size: 14px;
+  }
+}
+
+h4.help-dropdown-title {
+  font-size: 16px;
+  color: $blue;
+}
+
+.dropdown-items li.help-dropdown-service {
+  cursor: default;
+
+  &:hover {
+    background: inherit;
+  }
+
+  a {
+    display: inline;
+    color: $blue;
+  }
+}
+
+.help-dropdown-service-action {
+  margin-top: $default-padding;
+  margin-bottom: $default-spacer;
+}
+
+.help-dropdown-service-item {
+  margin-top: $default-spacer;
+  line-height: 18px;
+
+  .icon {
+    vertical-align: middle;
+    margin-right: 5px;
+
+    &.clock {
+      filter: contrast(0) brightness(120%);
+      vertical-align: -4px;
+    }
+  }
+}
+
diff --git a/app/controllers/new_user/dossiers_controller.rb b/app/controllers/new_user/dossiers_controller.rb
index b4bb54a99..44091e710 100644
--- a/app/controllers/new_user/dossiers_controller.rb
+++ b/app/controllers/new_user/dossiers_controller.rb
@@ -240,6 +240,11 @@ module NewUser
       flash.notice = 'La pièce jointe a bien été supprimée.'
     end
 
+    def dossier_for_help
+      dossier_id = params[:id] || params[:dossier_id]
+      @dossier || (dossier_id.present? && Dossier.find_by(id: dossier_id.to_i))
+    end
+
     private
 
     def store_user_location!
diff --git a/app/views/layouts/_new_header.haml b/app/views/layouts/_new_header.haml
index 81d141c51..6782ee596 100644
--- a/app/views/layouts/_new_header.haml
+++ b/app/views/layouts/_new_header.haml
@@ -1,5 +1,6 @@
-/ We can't use &. because the controller may not implement #nav_bar_profile
+-# We can't use &. because the controller may not implement #nav_bar_profile
 - nav_bar_profile = controller.try(:nav_bar_profile)
+- dossier = controller.try(:dossier_for_help)
 
 .new-header{ class: current_page?(root_path) ? nil : "new-header-with-border" }
   .header-inner-content
@@ -95,4 +96,7 @@
 
       %li
         .header-help
-          = link_to 'Aide', FAQ_URL, class: "button primary", target: "_blank", rel: "noopener"
+          - if nav_bar_profile == :user && dossier.present?
+            = render partial: 'new_user/dossier_help_dropdown', locals: { dossier: dossier }
+          - else
+            = link_to 'Aide', FAQ_URL, class: "button primary"
diff --git a/app/views/new_user/_dossier_help_dropdown.html.haml b/app/views/new_user/_dossier_help_dropdown.html.haml
new file mode 100644
index 000000000..275b7e1ac
--- /dev/null
+++ b/app/views/new_user/_dossier_help_dropdown.html.haml
@@ -0,0 +1,42 @@
+.dropdown.help-dropdown
+  .button.primary.dropdown-button Aide
+  .dropdown-content.fade-in-down
+    %ul.dropdown-items
+
+      - title = dossier.brouillon? ? "Besoin d’aide pour remplir votre dossier ?" : "Une question sur votre dossier ?"
+
+      - if dossier.messagerie_available?
+        -# Contact the administration using the messagerie
+        %li
+          = link_to messagerie_dossier_path(dossier) do
+            %span.icon.mail
+            .dropdown-description
+              %h4.help-dropdown-title= title
+              %p Envoyez directement un message à l’instructeur.
+
+      - elsif dossier.procedure.service.present?
+        - service = dossier.procedure.service
+        -# Contact the administration using email or phone
+        %li.help-dropdown-service
+          %span.icon.person
+          .dropdown-description
+            %h4.help-dropdown-title= title
+            .help-dropdown-service-action
+              %p Contactez directement l’administration :
+              %p.help-dropdown-service-item
+                %span.icon.small.mail
+                = link_to service.email, "mailto:#{service.email}"
+              %p.help-dropdown-service-item
+                %span.icon.small.phone
+                = link_to service.telephone, "tel:#{service.telephone}"
+              %p.help-dropdown-service-item
+                %span.icon.small.clock
+                = service.horaires
+
+      -# Use the help website
+      %li
+        = link_to FAQ_URL, target: "_blank", rel: "noopener" do
+          %span.icon.help
+          .dropdown-description
+            %h4.help-dropdown-title Un problème avec le site ?
+            %p Trouvez votre réponse dans l’aide en ligne.
diff --git a/spec/controllers/new_user/dossiers_controller_spec.rb b/spec/controllers/new_user/dossiers_controller_spec.rb
index a981b85b9..6d133d62b 100644
--- a/spec/controllers/new_user/dossiers_controller_spec.rb
+++ b/spec/controllers/new_user/dossiers_controller_spec.rb
@@ -952,4 +952,30 @@ describe NewUser::DossiersController, type: :controller do
       end
     end
   end
+
+  describe "#dossier_for_help" do
+    before do
+      sign_in(user)
+      controller.params[:dossier_id] = dossier_id.to_s
+    end
+
+    subject { controller.dossier_for_help }
+
+    context 'when the id matches an existing dossier' do
+      let(:dossier) { create(:dossier) }
+      let(:dossier_id) { dossier.id }
+
+      it { is_expected.to eq dossier }
+    end
+
+    context 'when the id doesn’t match an existing dossier' do
+      let(:dossier_id) { 9999999 }
+      it { is_expected.to be nil }
+    end
+
+    context 'when the id is empty' do
+      let(:dossier_id) { nil }
+      it { is_expected.to be_falsy }
+    end
+  end
 end
diff --git a/spec/features/help_spec.rb b/spec/features/help_spec.rb
new file mode 100644
index 000000000..b44fb6270
--- /dev/null
+++ b/spec/features/help_spec.rb
@@ -0,0 +1,84 @@
+require 'spec_helper'
+
+feature 'Getting help:' do
+  scenario 'a Help button is visible on public pages' do
+    visit '/'
+    within('.new-header') do
+      expect(page).to have_help_button
+    end
+  end
+
+  context 'as a signed-in user' do
+    let(:user) { create(:user) }
+    let(:procedure) { create(:procedure, :with_service) }
+
+    before do
+      login_as user, scope: :user
+    end
+
+    scenario 'a Help button is visible on signed-in pages' do
+      visit dossiers_path
+      within('.new-header') do
+        expect(page).to have_help_button
+      end
+    end
+
+    context 'on a page related to a draft dossier' do
+      let(:dossier) { create(:dossier, user: user, procedure: procedure) }
+
+      scenario 'a Help menu provides administration contacts and a link to the FAQ' do
+        visit dossier_path(dossier)
+
+        within('.new-header') do
+          expect(page).to have_help_menu
+        end
+
+        within('.help-dropdown') do
+          expect(page).to have_content(dossier.procedure.service.email)
+          expect(page).to have_content(dossier.procedure.service.telephone)
+          expect(page).to have_link(nil, href: FAQ_URL)
+        end
+      end
+    end
+
+    context 'on a page related to a submitted dossier' do
+      let(:dossier) { create(:dossier, :en_construction, user: user, procedure: procedure) }
+
+      scenario 'a Help menu provides links to the Messagerie and to the FAQ' do
+        visit dossier_path(dossier)
+
+        within('.new-header') do
+          expect(page).to have_help_menu
+        end
+
+        within('.help-dropdown') do
+          expect(page).to have_link(nil, href: messagerie_dossier_path(dossier))
+          expect(page).to have_link(nil, href: FAQ_URL)
+        end
+      end
+    end
+  end
+
+  context 'as a gestionnaire' do
+    let(:gestionnaire) { create(:gestionnaire) }
+
+    before do
+      login_as gestionnaire, scope: :gestionnaire
+    end
+
+    scenario 'a Help button is visible on signed-in pages' do
+      visit gestionnaire_procedures_path
+      within('.new-header') do
+        expect(page).to have_help_button
+      end
+    end
+  end
+
+  def have_help_button
+    have_link('Aide', href: FAQ_URL)
+  end
+
+  def have_help_menu
+    have_selector('.help-dropdown')
+  end
+end
diff --git a/spec/features/new_gestionnaire/gestionnaire_spec.rb b/spec/features/new_gestionnaire/gestionnaire_spec.rb
index e19676b0d..45b740660 100644
--- a/spec/features/new_gestionnaire/gestionnaire_spec.rb
+++ b/spec/features/new_gestionnaire/gestionnaire_spec.rb
@@ -54,7 +54,7 @@ feature 'The gestionnaire part' do
 
     click_on 'En instruction'
 
-    within('.dropdown-items') do
+    within('.state-button') do
       click_on 'Accepter'
     end
 
diff --git a/spec/views/layouts/_new_header_spec.rb b/spec/views/layouts/_new_header_spec.rb
index 17980f07e..373a14586 100644
--- a/spec/views/layouts/_new_header_spec.rb
+++ b/spec/views/layouts/_new_header_spec.rb
@@ -16,6 +16,10 @@ describe 'layouts/_new_header.html.haml', type: :view do
 
       it { is_expected.to have_css("a.header-logo[href=\"#{dossiers_path}\"]") }
       it { is_expected.to have_link("Dossiers", href: dossiers_path) }
+
+      it 'displays the Help button' do
+        expect(subject).to have_link("Aide", href: FAQ_URL)
+      end
     end
 
     context 'when rendering for gestionnaire' do