diff --git a/src/components/feature_type/FeatureTypeCustomForm.vue b/src/components/feature_type/FeatureTypeCustomForm.vue
index 5372073ee270dca4dba201cfdf927b089512c8f8..30b0a1e8014f0d788bc73e8d066b63de73315e2f 100644
--- a/src/components/feature_type/FeatureTypeCustomForm.vue
+++ b/src/components/feature_type/FeatureTypeCustomForm.vue
@@ -231,13 +231,23 @@ export default {
       },
       // * create an array, because backend expects an array
       set(newValue) {
+        this.form.options.errors = [];
         this.form.options.value = this.trimWhiteSpace(newValue).split(",");
-        this.updateStore();
+        if (this.hasDuplicates(this.form.options.value)) {
+          this.form.options.errors = [
+            "Veuillez saisir des valeurs différentes",
+          ];
+        } else {
+          this.updateStore();
+        }
       },
     },
   },
 
   methods: {
+    hasDuplicates(array) {
+      return new Set(array).size !== array.length;
+    },
     fillCustomFormData(customFormData) {
       for (let el in customFormData) {
         if (el && this.form[el] && customFormData[el]) {
diff --git a/src/views/feature_type/Feature_type_edit.vue b/src/views/feature_type/Feature_type_edit.vue
index 889b249c57ac0a46328cf403f68e8b9c612cdd3f..6a1cefd4068145799a5f4db9a25182acad1d6e35 100644
--- a/src/views/feature_type/Feature_type_edit.vue
+++ b/src/views/feature_type/Feature_type_edit.vue
@@ -277,10 +277,10 @@ export default {
       set(newValue) {
         console.log(newValue);
         const newColorsStyle = {
-          colors: {
-            [newValue.options[0]]: "#000000",
-            [newValue.options[1]]: "#000000",
-          },
+          colors: newValue.options.reduce((obj, key) => {
+            obj[key] = "#000000";
+            return obj;
+          }, {}),
           custom_field_name: newValue.value,
         };
         this.form.colors_style.value = newColorsStyle;