diff --git a/app/controllers/demandes_controller.rb b/app/controllers/demandes_controller.rb
index 312cde9e9..0975837b8 100644
--- a/app/controllers/demandes_controller.rb
+++ b/app/controllers/demandes_controller.rb
@@ -5,9 +5,12 @@ class DemandesController < ApplicationController
   end
 
   def update
-    @dossier = Dossier.find(params[:dossier_id])
-    @dossier.update_attributes(formulaire_id: params[:formulaire])
-
+    dossier = Dossier.find(params[:dossier_id])
+    if !dossier.formulaire.nil?
+      raise "La modification du formulaire n'est pas possible"
+    end
+    dossier.update_attributes(formulaire_id: params[:formulaire])
+    dossier.build_default_pieces_jointes
     redirect_to url_for(controller: :carte, action: :show, dossier_id: params[:dossier_id])
   end
 
diff --git a/app/models/dossier.rb b/app/models/dossier.rb
index d91564c4f..793ad4403 100644
--- a/app/models/dossier.rb
+++ b/app/models/dossier.rb
@@ -16,6 +16,12 @@ class Dossier < ActiveRecord::Base
     pieces_jointes.where(type_piece_jointe_id: piece_jointe_id).last
   end
 
+  def build_default_pieces_jointes
+    formulaire.types_piece_jointe.each do |type_piece_jointe|
+      PieceJointe.create(type_piece_jointe_id: type_piece_jointe.id, dossier_id: id)
+    end
+  end
+
   private
 
   def build_default_cerfa
diff --git a/spec/controllers/demandes_controller_spec.rb b/spec/controllers/demandes_controller_spec.rb
index 767cb643a..8ecaf5744 100644
--- a/spec/controllers/demandes_controller_spec.rb
+++ b/spec/controllers/demandes_controller_spec.rb
@@ -1,7 +1,7 @@
 require 'spec_helper'
 
 RSpec.describe DemandesController, type: :controller do
-  let(:dossier) { create(:dossier) }
+  let(:dossier) { create(:dossier, formulaire_id: '') }
   let (:dossier_id) { dossier.id }
 
   describe "GET #show" do
@@ -11,12 +11,19 @@ RSpec.describe DemandesController, type: :controller do
     end
   end
 
-  describe 'POST #choice' do
+  describe 'POST #upated' do
     context 'dans tous les cas on affiche la carte' do
       it {
-        post :update, :dossier_id => dossier_id, :type_demande => '1'
+        post :update, :dossier_id => dossier_id, :formulaire => '1'
         expect(response).to redirect_to(controller: :carte, action: :show, dossier_id: dossier_id)
       }
     end
+    context 'when dossier is already linked to formaulaire' do
+      let(:dossier) { create(:dossier) }
+      subject { post :update, :dossier_id => dossier_id, :formulaire => '1' }
+      it 'raise error' do
+        expect{subject}.to raise_error("La modification du formulaire n'est pas possible")
+      end
+    end
   end
 end
diff --git a/spec/models/dossier_spec.rb b/spec/models/dossier_spec.rb
index a98aaa6f5..4db38b186 100644
--- a/spec/models/dossier_spec.rb
+++ b/spec/models/dossier_spec.rb
@@ -63,4 +63,16 @@ describe Dossier do
       expect(dossier.cerfa).to eq(Cerfa.last)
     end
   end
+
+  describe '#build_default_pieces_jointes' do
+    context 'when dossier is linked to a formualire' do
+      let(:dossier) { create(:dossier) }
+      before do
+        dossier.build_default_pieces_jointes
+      end
+      it 'build all pieces jointes needed' do
+        expect(dossier.pieces_jointes.count).to eq(7)
+      end
+    end
+  end
 end
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