diff --git a/app/controllers/champs/carte_controller.rb b/app/controllers/champs/carte_controller.rb
index 9746896a5..3609272fd 100644
--- a/app/controllers/champs/carte_controller.rb
+++ b/app/controllers/champs/carte_controller.rb
@@ -1,6 +1,9 @@
 class Champs::CarteController < ApplicationController
   before_action :authenticate_logged_user!
 
+  EMPTY_GEO_JSON = '[]'
+  ERROR_GEO_JSON = ''
+
   def show
     @selector = ".carte-#{params[:position]}"
 
@@ -26,13 +29,17 @@ class Champs::CarteController < ApplicationController
     end
 
     geo_areas = []
-    geo_json = geo_json.blank? ? [] : JSON.parse(geo_json)
 
-    if geo_json.empty?
+    if geo_json == EMPTY_GEO_JSON
+      @champ.value = nil
+      @champ.geo_areas = []
+    elsif geo_json == ERROR_GEO_JSON
       @error = true
       @champ.value = nil
       @champ.geo_areas = []
-    elsif geo_json.present?
+    else
+      geo_json = JSON.parse(geo_json)
+
       if @champ.cadastres?
         cadastres = ModuleApiCartoService.generate_cadastre(geo_json)
         geo_areas += cadastres.map do |cadastre|
diff --git a/app/javascript/shared/carte.js b/app/javascript/shared/carte.js
index 1c7d7655e..a9360e829 100644
--- a/app/javascript/shared/carte.js
+++ b/app/javascript/shared/carte.js
@@ -107,15 +107,18 @@ export function getCurrentMap(input) {
   }
 }
 
+const EMPTY_GEO_JSON = '[]';
+const ERROR_GEO_JSON = '';
+
 export function addFreeDrawEvents(map, selector) {
   const input = findInput(selector);
   map.freeDraw.on('markers', ({ latLngs }) => {
     if (latLngs.length === 0) {
-      input.value = '';
+      input.value = EMPTY_GEO_JSON;
     } else if (polygonArea(latLngs) < 300000) {
       input.value = JSON.stringify(latLngs);
     } else {
-      input.value = '';
+      input.value = ERROR_GEO_JSON;
     }
 
     fire(input, 'change');
diff --git a/spec/controllers/champs/carte_controller_spec.rb b/spec/controllers/champs/carte_controller_spec.rb
index 9bd6c7627..6fbbd88e6 100644
--- a/spec/controllers/champs/carte_controller_spec.rb
+++ b/spec/controllers/champs/carte_controller_spec.rb
@@ -8,7 +8,7 @@ describe Champs::CarteController, type: :controller do
     {
       dossier: {
         champs_attributes: {
-          '1' => { value: selection.to_json }
+          '1' => { value: value }
         }
       },
       position: '1',
@@ -35,13 +35,18 @@ describe Champs::CarteController, type: :controller do
     end
 
     context 'when coordinates are empty' do
-      let(:selection) { [] }
+      let(:value) { '[]' }
 
-      it { expect(response.body).to include("DS.drawMapData(\".carte-1\", {\"position\":{\"lon\":\"2.428462\",\"lat\":\"46.538192\",\"zoom\":\"13\"},\"selection\":[],\"quartiersPrioritaires\":[],\"cadastres\":[],\"parcellesAgricoles\":[]});") }
+      it {
+        expect(assigns(:error)).to eq(nil)
+        expect(champ.reload.value).to eq(nil)
+        expect(champ.reload.geo_areas).to eq([])
+        expect(response.body).to include("DS.drawMapData(\".carte-1\", {\"position\":{\"lon\":\"2.428462\",\"lat\":\"46.538192\",\"zoom\":\"13\"},\"selection\":[],\"quartiersPrioritaires\":[],\"cadastres\":[],\"parcellesAgricoles\":[]});")
+      }
     end
 
     context 'when coordinates are informed' do
-      let(:selection) { [[{ "lat": 48.87442541960633, "lng": 2.3859214782714844 }, { "lat": 48.87273183590832, "lng": 2.3850631713867183 }, { "lat": 48.87081237174292, "lng": 2.3809432983398438 }, { "lat": 48.8712640169951, "lng": 2.377510070800781 }, { "lat": 48.87510283703279, "lng": 2.3778533935546875 }, { "lat": 48.87544154230615, "lng": 2.382831573486328 }, { "lat": 48.87442541960633, "lng": 2.3859214782714844 }]] }
+      let(:value) { [[{ "lat": 48.87442541960633, "lng": 2.3859214782714844 }, { "lat": 48.87273183590832, "lng": 2.3850631713867183 }, { "lat": 48.87081237174292, "lng": 2.3809432983398438 }, { "lat": 48.8712640169951, "lng": 2.377510070800781 }, { "lat": 48.87510283703279, "lng": 2.3778533935546875 }, { "lat": 48.87544154230615, "lng": 2.382831573486328 }, { "lat": 48.87442541960633, "lng": 2.3859214782714844 }]].to_json }
 
       it { expect(response.body).not_to be_nil }
       it { expect(response.body).to include('MultiPolygon') }
@@ -50,9 +55,10 @@ describe Champs::CarteController, type: :controller do
 
     context 'when error' do
       let(:geojson) { [[{ "lat": 48.87442541960633, "lng": 2.3859214782714844 }, { "lat": 48.87273183590832, "lng": 2.3850631713867183 }, { "lat": 48.87081237174292, "lng": 2.3809432983398438 }, { "lat": 48.8712640169951, "lng": 2.377510070800781 }, { "lat": 48.87510283703279, "lng": 2.3778533935546875 }, { "lat": 48.87544154230615, "lng": 2.382831573486328 }, { "lat": 48.87442541960633, "lng": 2.3859214782714844 }]] }
-      let(:selection) { '' }
+      let(:value) { '' }
 
       it {
+        expect(assigns(:error)).to eq(true)
         expect(champ.reload.value).to eq(nil)
         expect(champ.reload.geo_areas).to eq([])
       }