diff --git a/app/assets/stylesheets/start.scss b/app/assets/stylesheets/siret.scss
similarity index 100%
rename from app/assets/stylesheets/start.scss
rename to app/assets/stylesheets/siret.scss
diff --git a/app/controllers/backoffice/dossiers_controller.rb b/app/controllers/backoffice/dossiers_controller.rb
index 189cbab65..e1f4c96ec 100644
--- a/app/controllers/backoffice/dossiers_controller.rb
+++ b/app/controllers/backoffice/dossiers_controller.rb
@@ -14,12 +14,8 @@ class Backoffice::DossiersController < ApplicationController
 
     @dossier = @dossier.decorate
   rescue ActiveRecord::RecordNotFound
-    redirect_start
+    flash.alert = t('errors.messages.dossier_not_found')
+    redirect_to url_for(controller: '/backoffice')
   end
 
-  private
-
-  def redirect_start
-    redirect_to url_for(controller: '/start', action: :error_dossier)
-  end
 end
diff --git a/app/controllers/carte_controller.rb b/app/controllers/carte_controller.rb
index d36f24d14..2e11af799 100644
--- a/app/controllers/carte_controller.rb
+++ b/app/controllers/carte_controller.rb
@@ -4,7 +4,7 @@ class CarteController < ApplicationController
   def show
     @dossier = current_dossier
   rescue ActiveRecord::RecordNotFound
-    redirect_to url_for(controller: :start, action: :error_dossier)
+    redirect_to url_for(controller: :siret, action: :error_dossier)
   end
 
   def save_ref_api_carto
diff --git a/app/controllers/description_controller.rb b/app/controllers/description_controller.rb
index 7835f1e00..ba492d6b3 100644
--- a/app/controllers/description_controller.rb
+++ b/app/controllers/description_controller.rb
@@ -6,7 +6,8 @@ class DescriptionController < ApplicationController
     @procedure = @dossier.procedure
 
   rescue ActiveRecord::RecordNotFound
-    redirect_to url_for(controller: :start, action: :error_dossier)
+    flash.alert = t('errors.messages.dossier_not_found')
+    redirect_to url_for(controller: :siret)
   end
 
   def error
diff --git a/app/controllers/dossiers_controller.rb b/app/controllers/dossiers_controller.rb
index 07e27a368..240400bcd 100644
--- a/app/controllers/dossiers_controller.rb
+++ b/app/controllers/dossiers_controller.rb
@@ -5,16 +5,18 @@ class DossiersController < ApplicationController
     @etablissement =  @dossier.etablissement
     @entreprise =  @dossier.entreprise.decorate
   rescue ActiveRecord::RecordNotFound
-    redirect_to url_for(controller: :start, action: :error_dossier)
+    flash.alert = t('errors.messages.dossier_not_found')
+    redirect_to url_for(controller: :siret)
   end
 
   def create
+    procedure = Procedure.find(params['procedure_id'])
     @etablissement = Etablissement.new(SIADE::EtablissementAdapter.new(siret).to_params)
     @entreprise = Entreprise.new(SIADE::EntrepriseAdapter.new(siren).to_params)
     @dossier = Dossier.create
     @dossier.draft!
 
-    @dossier.procedure = Procedure.find(params['procedure_id'])
+    @dossier.procedure = procedure
     @dossier.save
 
     @entreprise.dossier = @dossier
@@ -27,9 +29,11 @@ class DossiersController < ApplicationController
     redirect_to url_for(controller: :dossiers, action: :show, id: @dossier.id)
 
   rescue RestClient::ResourceNotFound
-    redirect_to url_for(controller: :start, action: :error_siret, procedure_id: params['procedure_id'])
+    flash.alert = t('errors.messages.invalid_siret')
+    redirect_to url_for(controller: :siret, procedure_id: params['procedure_id'])
   rescue ActiveRecord::RecordNotFound
-    redirect_to url_for(controller: :start, action: :error_dossier)
+    flash.alert = t('errors.messages.dossier_not_found')
+    redirect_to url_for(controller: :siret)
   end
 
   def update
diff --git a/app/controllers/recapitulatif_controller.rb b/app/controllers/recapitulatif_controller.rb
index 194cd0f0e..4552dbc3b 100644
--- a/app/controllers/recapitulatif_controller.rb
+++ b/app/controllers/recapitulatif_controller.rb
@@ -11,6 +11,7 @@ class RecapitulatifController < ApplicationController
     #TODO load user email
     @commentaire_email = 'user@email'
   rescue ActiveRecord::RecordNotFound
-    redirect_to url_for(controller: :start, action: :error_dossier)
+    flash.alert = t('errors.messages.dossier_not_found')
+    redirect_to url_for(controller: :siret)
   end
 end
diff --git a/app/controllers/siret_controller.rb b/app/controllers/siret_controller.rb
new file mode 100644
index 000000000..5f5bb976f
--- /dev/null
+++ b/app/controllers/siret_controller.rb
@@ -0,0 +1,13 @@
+class SiretController < ApplicationController
+  before_action :authenticate_user!
+  def index
+    @procedure = Procedure.find(params['procedure_id'])
+  rescue ActiveRecord::RecordNotFound
+    error_procedure
+  end
+
+  def error_procedure
+    render :file => "#{Rails.root}/public/404_procedure_not_found.html",  :status => 404
+  end
+
+end
diff --git a/app/controllers/start_controller.rb b/app/controllers/start_controller.rb
deleted file mode 100644
index 51eb5a053..000000000
--- a/app/controllers/start_controller.rb
+++ /dev/null
@@ -1,38 +0,0 @@
-class StartController < ApplicationController
-  before_action :authenticate_user!
-  def index
-    get_procedure_infos
-
-    if @procedure.nil?
-      error_procedure
-    end
-  rescue ActiveRecord::RecordNotFound
-    error_procedure
-  end
-
-  def error_procedure
-    render :file => "#{Rails.root}/public/404_procedure_not_found.html",  :status => 404
-  end
-
-  def error_siret
-    get_procedure_infos
-    flash.now.alert = 'Ce SIRET n\'est pas valide'
-    render 'index'
-  end
-
-  def error_login
-    flash.now.alert = 'Ce compte n\'existe pas'
-    render 'index'
-  end
-
-  def error_dossier
-    flash.now.alert = 'Ce dossier n\'existe pas'
-    render 'index'
-  end
-
-  private
-
-  def get_procedure_infos
-    @procedure = Procedure.find(params['procedure_id'])
-  end
-end
diff --git a/app/views/start/_admin.html.haml b/app/views/siret/_admin.html.haml
similarity index 100%
rename from app/views/start/_admin.html.haml
rename to app/views/siret/_admin.html.haml
diff --git a/app/views/start/_pro.html.haml b/app/views/siret/_pro.html.haml
similarity index 100%
rename from app/views/start/_pro.html.haml
rename to app/views/siret/_pro.html.haml
diff --git a/app/views/start/index.html.haml b/app/views/siret/index.html.haml
similarity index 92%
rename from app/views/start/index.html.haml
rename to app/views/siret/index.html.haml
index fe9aa62d7..215baf74a 100644
--- a/app/views/start/index.html.haml
+++ b/app/views/siret/index.html.haml
@@ -5,5 +5,5 @@
     Site de démonstration d’un service public de saisie d’un projet ou de dépôt d’une démarche administrative, auprès d’un ou plusieurs organismes publics, simplifié des informations déjà connues des administrations, grâce à la fourniture du numéro SIRET.
 
   .row
-    = render partial: '/start/pro'
+    = render partial: '/siret/pro'
 
diff --git a/config/locales/fr.yml b/config/locales/fr.yml
index 6591b7048..dff830200 100644
--- a/config/locales/fr.yml
+++ b/config/locales/fr.yml
@@ -78,5 +78,7 @@ fr:
       not_saved:
         one: "1 erreur a empêché ce(tte) %{resource} d'être sauvegardé(e) :"
         other: "%{count} erreurs ont empêché ce(tte) %{resource} d'être sauvegardé(e) :"
+      dossier_not_found: "Le dossier n'existe pas"
+      invalid_siret: "Le siret est incorrect"
 
 
diff --git a/config/routes.rb b/config/routes.rb
index a192e08dd..69b95450a 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -12,11 +12,11 @@ Rails.application.routes.draw do
   # root 'welcome#index'
   root 'users/dossiers#index'
 
-  get 'start' => 'start#index'
-  get 'start/index'
-  get 'start/error_siret'
-  get 'start/error_login'
-  get 'start/error_dossier'
+  get 'siret' => 'siret#index'
+  # get 'start/index'
+  # get 'start/error_siret'
+  # get 'start/error_login'
+  # get 'start/error_dossier'
 
   resources :dossiers do
     get '/demande' => 'demandes#show'
diff --git a/spec/controllers/backoffice/dossiers_controller_spec.rb b/spec/controllers/backoffice/dossiers_controller_spec.rb
index 7023432df..da789d0e4 100644
--- a/spec/controllers/backoffice/dossiers_controller_spec.rb
+++ b/spec/controllers/backoffice/dossiers_controller_spec.rb
@@ -19,7 +19,7 @@ describe Backoffice::DossiersController, type: :controller do
 
       it "le numéro de dossier n'existe pas" do
         get :show, id: bad_dossier_id
-        expect(response).to redirect_to('/start/error_dossier')
+        expect(response).to redirect_to('/backoffice')
       end
     end
 
diff --git a/spec/controllers/description_controller_spec.rb b/spec/controllers/description_controller_spec.rb
index 894378bd9..1998f2258 100644
--- a/spec/controllers/description_controller_spec.rb
+++ b/spec/controllers/description_controller_spec.rb
@@ -13,7 +13,7 @@ describe DescriptionController, type: :controller do
 
     it 'redirection vers start si mauvais dossier ID' do
       get :show, dossier_id: bad_dossier_id
-      expect(response).to redirect_to(controller: :start, action: :error_dossier)
+      expect(response).to redirect_to(controller: :siret)
     end
   end
 
diff --git a/spec/controllers/dossiers_controller_spec.rb b/spec/controllers/dossiers_controller_spec.rb
index 9a235e65f..6c2f5d478 100644
--- a/spec/controllers/dossiers_controller_spec.rb
+++ b/spec/controllers/dossiers_controller_spec.rb
@@ -2,6 +2,7 @@ require 'spec_helper'
 
 describe DossiersController, type: :controller do
   let(:dossier) { create(:dossier, :with_entreprise, :with_procedure) }
+  let(:procedure) { create(:procedure) }
   let(:dossier_id) { dossier.id }
   let(:siret_not_found) { 999_999_999_999 }
 
@@ -15,9 +16,9 @@ describe DossiersController, type: :controller do
       expect(response).to have_http_status(:success)
     end
 
-    it 'redirection vers start si mauvais dossier ID' do
+    it 'redirection vers siret si mauvais dossier ID' do
       get :show, id: siret_not_found
-      expect(response).to redirect_to('/start/error_dossier')
+      expect(response).to redirect_to('/siret')
     end
   end
 
@@ -36,16 +37,16 @@ describe DossiersController, type: :controller do
     describe 'professionnel fills form' do
       context 'when pro_dossier_id is empty' do
         context 'with valid siret ' do
-          before do
-            post :create, siret: siret, pro_dossier_id: '', procedure_id: Procedure.last
-          end
+
+          subject  { post :create, siret: siret, pro_dossier_id: '', procedure_id: Procedure.last }
+
 
           it 'create a dossier' do
-            expect { post :create, siret: siret, pro_dossier_id: '' }.to change { Dossier.count }.by(1)
+            expect { subject }.to change { Dossier.count }.by(1)
           end
 
           it 'creates entreprise' do
-            expect { post :create, siret: siret, pro_dossier_id: '', procedure_id: Procedure.last }.to change { Entreprise.count }.by(1)
+            expect { subject }.to change { Entreprise.count }.by(1)
           end
 
           it 'links entreprise to dossier' do
@@ -53,35 +54,39 @@ describe DossiersController, type: :controller do
           end
 
           it 'creates etablissement for dossier' do
-            expect { post :create, siret: siret, pro_dossier_id: '', procedure_id: Procedure.last }.to change { Etablissement.count }.by(1)
+            expect { subject }.to change { Etablissement.count }.by(1)
           end
 
           it 'links etablissement to dossier' do
+            subject
             expect(Etablissement.last.dossier).to eq(Dossier.last)
           end
 
           it 'links etablissement to entreprise' do
+            subject
             expect(Etablissement.last.entreprise).to eq(Entreprise.last)
           end
 
           it 'links procedure to dossier' do
+            subject
             expect(Dossier.last.procedure).to eq(Procedure.last)
           end
 
           it 'state of dossier is draft' do
+            subject
             expect(Dossier.last.state).to eq('draft')
           end
         end
 
         context 'with non existant siret' do
           let(:siret_not_found) { '11111111111111' }
-          subject { post :create, siret: siret_not_found, pro_dossier_id: '' }
+          subject { post :create, siret: siret_not_found, pro_dossier_id: '', procedure_id: procedure.id }
           it 'does not create new dossier' do
             expect { subject }.not_to change { Dossier.count }
           end
 
           it 'redirects to show' do
-            expect(subject).to redirect_to(controller: :start, action: :error_siret)
+            expect(subject).to redirect_to(controller: :siret, procedure_id: procedure.id)
           end
         end
       end
diff --git a/spec/controllers/recapitulatif_controller_spec.rb b/spec/controllers/recapitulatif_controller_spec.rb
index 609ddbf22..1d572121a 100644
--- a/spec/controllers/recapitulatif_controller_spec.rb
+++ b/spec/controllers/recapitulatif_controller_spec.rb
@@ -11,9 +11,9 @@ RSpec.describe RecapitulatifController, type: :controller do
       expect(response).to have_http_status(:success)
     end
 
-    it 'redirection vers start si mauvais dossier ID' do
+    it 'redirection vers siret si mauvais dossier ID' do
       get :show, dossier_id: bad_dossier_id
-      expect(response).to redirect_to('/start/error_dossier')
+      expect(response).to redirect_to('/siret')
     end
   end
 end
diff --git a/spec/controllers/start_controller_spec.rb b/spec/controllers/siret_controller_spec.rb
similarity index 98%
rename from spec/controllers/start_controller_spec.rb
rename to spec/controllers/siret_controller_spec.rb
index 57a19bf0c..e169a8fd7 100644
--- a/spec/controllers/start_controller_spec.rb
+++ b/spec/controllers/siret_controller_spec.rb
@@ -1,6 +1,6 @@
 require 'spec_helper'
 
-describe StartController, type: :controller do
+describe SiretController, type: :controller do
   let!(:procedure) { create(:procedure) }
 
   describe 'GET #index' do
diff --git a/spec/features/users/start_demande_spec.rb b/spec/features/users/start_demande_spec.rb
index c073aab62..1da39fcc2 100644
--- a/spec/features/users/start_demande_spec.rb
+++ b/spec/features/users/start_demande_spec.rb
@@ -1,13 +1,13 @@
 require 'spec_helper'
 
-feature 'user arrive on start page' do
+feature 'user arrive on siret page' do
   let(:procedure) { create(:procedure) }
   let(:user) { create(:user) }
   let(:siret) { '42149333900020' }
   let(:siren) { siret[0...9] }
   context 'when user is not logged in' do
     before do
-      visit start_path(procedure_id: procedure.id)
+      visit siret_path(procedure_id: procedure.id)
     end
     scenario 'he is redirected to login page' do
       expect(page).to have_css('#login_user')
@@ -18,7 +18,7 @@ feature 'user arrive on start page' do
         page.find_by_id('user_password').set user.password
         page.click_on 'Se connecter'
       end
-      scenario 'he is redirected to start page to enter a siret' do
+      scenario 'he is redirected to siret page to enter a siret' do
         expect(page).to have_css('#pro_section')
       end
       context 'when enter a siret' do
diff --git a/spec/views/start/index.html.haml_spec.rb b/spec/views/siret/index.html.haml_spec.rb
similarity index 95%
rename from spec/views/start/index.html.haml_spec.rb
rename to spec/views/siret/index.html.haml_spec.rb
index b4334cbb7..9d27ae043 100644
--- a/spec/views/start/index.html.haml_spec.rb
+++ b/spec/views/siret/index.html.haml_spec.rb
@@ -1,6 +1,6 @@
 require 'spec_helper'
 
-describe 'start/index.html.haml', type: :view do
+describe 'siret/index.html.haml', type: :view do
   let(:procedure) { create(:procedure, libelle: 'Demande de subvention') }
   before do
     assign(:procedure, procedure)