diff --git a/src/components/vmd-departement-selector.component.ts b/src/components/vmd-departement-selector.component.ts
index 1e663e10e..06c3f0d8a 100644
--- a/src/components/vmd-departement-selector.component.ts
+++ b/src/components/vmd-departement-selector.component.ts
@@ -23,7 +23,7 @@ export class VmdDepartementSelectorComponent extends LitElement {
 
     render() {
         return html`
-            <select class="form-select form-select-lg" @change="${this.departementSelectionne}">
+            <select class="form-select form-select-lg" @change="${this.departementSelectionne}" required>
               <option value="" ?selected="${!this.codeDepartementSelectionne}" disabled>Sélectionner...</option>
               ${repeat(this.departementsDisponibles, (dept) => dept.code_departement, (dept) => {
                 return html`
diff --git a/src/styles/global.scss b/src/styles/global.scss
index a4f406460..135d5c924 100644
--- a/src/styles/global.scss
+++ b/src/styles/global.scss
@@ -34,3 +34,7 @@ footer {
 h1 {
     font-weight: bold;
 }
+
+select[required]:invalid {
+    color: $gray-600;
+}