diff --git a/app/controllers/backoffice/private_formulaires_controller.rb b/app/controllers/backoffice/private_formulaires_controller.rb
index 8a9283959..81a728085 100644
--- a/app/controllers/backoffice/private_formulaires_controller.rb
+++ b/app/controllers/backoffice/private_formulaires_controller.rb
@@ -5,7 +5,7 @@ class Backoffice::PrivateFormulairesController < ApplicationController
     dossier = current_gestionnaire.dossiers.find(params[:dossier_id])
 
     unless params[:champs].nil?
-      champs_service_errors = ChampsService.save_formulaire dossier.champs_private, params
+      champs_service_errors = ChampsService.save_champs dossier.champs_private, params
 
       if champs_service_errors.empty?
         flash[:notice] = "Formulaire enregistré"
diff --git a/app/controllers/users/description_controller.rb b/app/controllers/users/description_controller.rb
index 71bc8aa29..e8d83cd20 100644
--- a/app/controllers/users/description_controller.rb
+++ b/app/controllers/users/description_controller.rb
@@ -34,18 +34,12 @@ class Users::DescriptionController < UsersController
 
     @champs = @dossier.ordered_champs
 
-    mandatory = true
-    mandatory = !(params[:submit].keys.first == 'brouillon') unless params[:submit].nil?
+    check_mandatory_fields = !draft_submission?
 
-    unless @dossier.update_attributes(create_params)
-      @dossier = @dossier.decorate
-
-      flash.alert = @dossier.errors.full_messages.join('<br />').html_safe
-      return redirect_to users_dossier_description_path(dossier_id: @dossier.id)
-    end
-
-    unless params[:champs].nil?
-      champs_service_errors = ChampsService.save_formulaire @dossier.champs, params, mandatory
+    if params[:champs]
+      champs_service_errors = ChampsService.save_champs @dossier.champs,
+                                                        params,
+                                                        check_mandatory_fields
 
       unless champs_service_errors.empty?
         flash.alert = (champs_service_errors.inject('') { |acc, error| acc+= error[:message]+'<br>' }).html_safe
@@ -53,33 +47,30 @@ class Users::DescriptionController < UsersController
       end
     end
 
-    if @procedure.cerfa_flag?
-      unless params[:cerfa_pdf].nil?
-        cerfa = Cerfa.new(content: params[:cerfa_pdf], dossier: @dossier, user: current_user)
-        unless cerfa.save
-          flash.alert = cerfa.errors.full_messages.join('<br />').html_safe
-          return redirect_to users_dossier_description_path(dossier_id: @dossier.id)
-        end
+    if @procedure.cerfa_flag? && params[:cerfa_pdf]
+      cerfa = Cerfa.new(content: params[:cerfa_pdf], dossier: @dossier, user: current_user)
+      unless cerfa.save
+        flash.alert = cerfa.errors.full_messages.join('<br />').html_safe
+        return redirect_to users_dossier_description_path(dossier_id: @dossier.id)
       end
     end
 
-    unless (errors_upload = PiecesJustificativesService.upload!(@dossier, current_user, params)).empty?
+    errors_upload = PiecesJustificativesService.upload!(@dossier, current_user, params)
+    unless errors_upload.empty?
       flash.alert = errors_upload.html_safe
       return redirect_to users_dossier_description_path(dossier_id: @dossier.id)
     end
 
-
-    if mandatory
+    if draft_submission?
+      flash.notice = 'Votre brouillon a bien été sauvegardé.'
+      redirect_to url_for(controller: :dossiers, action: :index, liste: :brouillon)
+    else
       if @dossier.draft?
         @dossier.initiated!
         NotificationMailer.send_notification(@dossier, @dossier.procedure.initiated_mail).deliver_now!
       end
-
       flash.notice = 'Félicitations, votre demande a bien été enregistrée.'
       redirect_to url_for(controller: :recapitulatif, action: :show, dossier_id: @dossier.id)
-    else
-      flash.notice = 'Votre brouillon a bien été sauvegardé.'
-      redirect_to url_for(controller: :dossiers, action: :index, liste: :brouillon)
     end
   end
 
@@ -123,6 +114,10 @@ class Users::DescriptionController < UsersController
 
   private
 
+  def draft_submission?
+    params[:submit] && params[:submit].keys.first == 'brouillon'
+  end
+
   def check_autorisation_donnees
     @dossier = current_user_dossier
 
@@ -137,9 +132,4 @@ class Users::DescriptionController < UsersController
       redirect_to url_for(users_dossier_path(@dossier.id))
     end
   end
-
-  def create_params
-    params.permit()
-  end
-
 end
diff --git a/app/models/champ.rb b/app/models/champ.rb
index e4a6e820e..ce12e32a3 100644
--- a/app/models/champ.rb
+++ b/app/models/champ.rb
@@ -28,6 +28,10 @@ class Champ < ActiveRecord::Base
     same_date? num, '%M'
   end
 
+  def mandatory_and_blank?
+    mandatory? && value.blank?
+  end
+
   def same_date? num, compare
     if type_champ == 'datetime' && !value.nil?
       if value.to_datetime.strftime(compare) == num
diff --git a/app/services/champs_service.rb b/app/services/champs_service.rb
index 04fdf9602..31b53973f 100644
--- a/app/services/champs_service.rb
+++ b/app/services/champs_service.rb
@@ -1,27 +1,41 @@
 class ChampsService
-  def self.save_formulaire champs, params, check_mandatory=true
-    errors = Array.new
+  class << self
+    def save_champs(champs, params, check_mandatory = true)
+      fill_champs(champs, params)
 
-    champs.each do |champ|
-      champ.value = params[:champs]["'#{champ.id}'"]
+      champs.select(&:changed?).each(&:save)
 
-      if champ.type_champ == 'datetime'
-        champ.value = params[:champs]["'#{champ.id}'"]+
-            ' ' +
-            params[:time_hour]["'#{champ.id}'"] +
-            ':' +
-            params[:time_minute]["'#{champ.id}'"]
-      end
-
-      if check_mandatory
-        if champ.mandatory? && (champ.value.nil? || champ.value.blank?)
-          errors.push({message: "Le champ #{champ.libelle} doit être rempli."})
-        end
-      end
-
-      champ.save if champ.changed?
+      check_mandatory ? build_error_messages(champs) : []
     end
 
-    errors
+    private
+
+    def fill_champs(champs, h)
+      datetimes, not_datetimes = champs.partition { |c| c.type_champ == 'datetime' }
+
+      not_datetimes.each { |c| c.value = h[:champs]["'#{c.id}'"] }
+      datetimes.each { |c| c.value = parse_datetime(c.id, h) }
+    end
+
+    def parse_datetime(champ_id, h)
+      "#{h[:champs]["'#{champ_id}'"]} #{extract_hour(champ_id, h)}:#{extract_minute(champ_id, h)}"
+    end
+
+    def extract_hour(champ_id, h)
+      h[:time_hour]["'#{champ_id}'"]
+    end
+
+    def extract_minute(champ_id, h)
+      h[:time_minute]["'#{champ_id}'"]
+    end
+
+    def build_error_messages(champs)
+      champs.select(&:mandatory_and_blank?)
+            .map { |c| build_champ_error_message(c) }
+    end
+
+    def build_champ_error_message(champ)
+      { message: "Le champ #{champ.libelle} doit être rempli." }
+    end
   end
 end
diff --git a/spec/models/champ_shared_example.rb b/spec/models/champ_shared_example.rb
index 9922fd38d..b404154df 100644
--- a/spec/models/champ_shared_example.rb
+++ b/spec/models/champ_shared_example.rb
@@ -14,6 +14,33 @@ shared_examples 'champ_spec' do
     it { is_expected.to delegate_method(:order_place).to(:type_de_champ) }
   end
 
+  describe 'mandatory_and_blank?' do
+    let(:type_de_champ) { TypeDeChamp.new(mandatory: mandatory) }
+    let(:champ) { Champ.new(type_de_champ: type_de_champ, value: value) }
+    let(:value) { '' }
+    let(:mandatory) { true }
+
+    context 'when mandatory and blank' do
+      it { expect(champ.mandatory_and_blank?).to be(true) }
+    end
+
+    context 'when not blank' do
+      let(:value) { 'yop' }
+      it { expect(champ.mandatory_and_blank?).to be(false) }
+    end
+
+    context 'when not mandatory' do
+      let(:mandatory) { false }
+      it { expect(champ.mandatory_and_blank?).to be(false) }
+    end
+
+    context 'when not mandatory or blank' do
+      let(:value) { 'u' }
+      let(:mandatory) { false }
+      it { expect(champ.mandatory_and_blank?).to be(false) }
+    end
+  end
+
   describe 'data_provide' do
     let(:champ) { create :champ }
 
diff --git a/spec/services/champs_service_spec.rb b/spec/services/champs_service_spec.rb
new file mode 100644
index 000000000..4e8ce53a1
--- /dev/null
+++ b/spec/services/champs_service_spec.rb
@@ -0,0 +1,49 @@
+require 'spec_helper'
+
+describe ChampsService do
+  describe 'save_champs' do
+    let!(:champ) { Champ.create(value: 'toto', type_de_champ: TypeDeChamp.new) }
+    let!(:champ_mandatory_empty) { Champ.create(type_de_champ: TypeDeChamp.new(libelle: 'mandatory', mandatory: true)) }
+    let!(:champ_datetime) do
+      champ_datetime = TypeDeChamp.new(type_champ: 'datetime')
+      Champ.create(type_de_champ: champ_datetime)
+    end
+    let!(:champs) { [champ, champ_mandatory_empty, champ_datetime] }
+
+    before :each do
+      params_hash = {
+        champs: {
+          "'#{champ.id}'" => 'yop',
+          "'#{champ_datetime.id}'" => 'd'
+        },
+        time_hour:  { "'#{champ_datetime.id}'" => '12' },
+        time_minute: { "'#{champ_datetime.id}'" => '24' }
+      }
+      @errors = ChampsService.save_champs(champs, params_hash, check_mandatory)
+      champs.each(&:reload)
+    end
+
+    context 'check_mandatory is true' do
+      let(:check_mandatory) { true }
+      it 'saves the changed champ' do
+        expect(champ.value).to eq('yop')
+      end
+
+      it 'parses and save the date' do
+        expect(champ_datetime.value).to eq('d 12:24')
+      end
+
+      it 'adds error for the missing mandatory champ' do
+        expect(@errors).to match([{ message: 'Le champ mandatory doit être rempli.' }])
+      end
+    end
+
+    context 'check_mandatory is false' do
+      let(:check_mandatory) { false }
+
+      it 'does not add errors' do
+        expect(@errors).to match([])
+      end
+    end
+  end
+end