diff --git a/app/models/types_de_champ/linked_drop_down_list_type_de_champ.rb b/app/models/types_de_champ/linked_drop_down_list_type_de_champ.rb
index 904e05a40..a90b7a0f0 100644
--- a/app/models/types_de_champ/linked_drop_down_list_type_de_champ.rb
+++ b/app/models/types_de_champ/linked_drop_down_list_type_de_champ.rb
@@ -3,6 +3,8 @@ class TypesDeChamp::LinkedDropDownListTypeDeChamp < TypesDeChamp::TypeDeChampBas
 
   delegate :drop_down_list, to: :@type_de_champ
 
+  validate :check_presence_of_primary_options
+
   def primary_options
     primary_options = unpack_options.map(&:first)
     if primary_options.present?
@@ -21,6 +23,12 @@ class TypesDeChamp::LinkedDropDownListTypeDeChamp < TypesDeChamp::TypeDeChampBas
 
   private
 
+  def check_presence_of_primary_options
+    if !PRIMARY_PATTERN.match?(drop_down_list.options.second)
+      errors.add(libelle, "doit commencer par une entrée de menu primaire de la forme <code style='white-space: pre-wrap;'>--texte--</code>")
+    end
+  end
+
   def unpack_options
     _, *options = drop_down_list.options
     chunked = options.slice_before(PRIMARY_PATTERN)
diff --git a/app/models/types_de_champ/type_de_champ_base.rb b/app/models/types_de_champ/type_de_champ_base.rb
index a7053dc38..4f77596c3 100644
--- a/app/models/types_de_champ/type_de_champ_base.rb
+++ b/app/models/types_de_champ/type_de_champ_base.rb
@@ -1,6 +1,8 @@
 class TypesDeChamp::TypeDeChampBase
   include ActiveModel::Validations
 
+  delegate :libelle, to: :@type_de_champ
+
   def initialize(type_de_champ)
     @type_de_champ = type_de_champ
   end
diff --git a/spec/factories/type_de_champ.rb b/spec/factories/type_de_champ.rb
index c208f5aac..363b79476 100644
--- a/spec/factories/type_de_champ.rb
+++ b/spec/factories/type_de_champ.rb
@@ -54,7 +54,7 @@ FactoryBot.define do
     end
     factory :type_de_champ_linked_drop_down_list do
       type_champ { TypeDeChamp.type_champs.fetch(:linked_drop_down_list) }
-      drop_down_list { create(:drop_down_list) }
+      drop_down_list { create(:drop_down_list, value: "--primary--\nsecondary\n") }
     end
     factory :type_de_champ_pays do
       type_champ { TypeDeChamp.type_champs.fetch(:pays) }
diff --git a/spec/models/types_de_champ/linked_drop_down_list_type_de_champ_spec.rb b/spec/models/types_de_champ/linked_drop_down_list_type_de_champ_spec.rb
index f9bc0af6a..b7ee29bdf 100644
--- a/spec/models/types_de_champ/linked_drop_down_list_type_de_champ_spec.rb
+++ b/spec/models/types_de_champ/linked_drop_down_list_type_de_champ_spec.rb
@@ -1,12 +1,78 @@
 require 'spec_helper'
 
 describe TypesDeChamp::LinkedDropDownListTypeDeChamp do
+  let(:drop_down_list) { build(:drop_down_list, value: menu_options) }
+  let(:type_de_champ) { build(:type_de_champ_linked_drop_down_list, drop_down_list: drop_down_list) }
+
+  subject { type_de_champ.dynamic_type }
+
+  describe 'validation' do
+    context 'It must start with one primary option' do
+      context 'valid menu' do
+        let(:menu_options) do
+          <<~END_OPTIONS
+            --Primary 1--
+            secondary 1.1
+            secondary 1.2
+            --Primary 2--
+            secondary 2.1
+            secondary 2.2
+            secondary 2.3
+          END_OPTIONS
+        end
+
+        it { is_expected.to be_valid }
+      end
+
+      context 'degenerate but valid menu' do
+        let(:menu_options) do
+          <<~END_OPTIONS
+            --Primary 1--
+          END_OPTIONS
+        end
+
+        it { is_expected.to be_valid }
+      end
+
+      context 'invalid menus' do
+        shared_examples 'missing primary option' do
+          it { is_expected.to be_invalid }
+          it do
+            subject.validate
+            expect(subject.errors.full_messages).to eq ["#{subject.libelle} doit commencer par une entrée de menu primaire de la forme <code style='white-space: pre-wrap;'>--texte--</code>"]
+          end
+        end
+
+        context 'no primary option' do
+          let(:menu_options) do
+            <<~END_OPTIONS
+              secondary 1.1
+              secondary 1.2
+            END_OPTIONS
+          end
+
+          it_should_behave_like 'missing primary option'
+        end
+
+        context 'starting with secondary options' do
+          let(:menu_options) do
+            <<~END_OPTIONS
+              secondary 1.1
+              secondary 1.2
+              --Primary 2--
+              secondary 2.1
+              secondary 2.2
+              secondary 2.3
+            END_OPTIONS
+          end
+
+          it_should_behave_like 'missing primary option'
+        end
+      end
+    end
+  end
+
   describe '#unpack_options' do
-    let(:drop_down_list) { build(:drop_down_list, value: menu_options) }
-    let(:type_de_champ) { build(:type_de_champ_linked_drop_down_list, drop_down_list: drop_down_list) }
-
-    subject { type_de_champ.dynamic_type }
-
     context 'with no options' do
       let(:menu_options) { '' }
       it { expect(subject.secondary_options).to eq({}) }