diff --git a/ecrire/bootstrap/inc/utils.php b/ecrire/bootstrap/inc/utils.php
index 7968e51fafa019e743362dd5d28836284c37d837..54c4571ff27975d4ad7e8a94b529401fcbdb5295 100644
--- a/ecrire/bootstrap/inc/utils.php
+++ b/ecrire/bootstrap/inc/utils.php
@@ -21,7 +21,7 @@ function test_plugin_actif($plugin) {
  * @param string $rep Chemin d’un répertoire
  * @return string
  */
-function joli_repertoire($rep) {
+function joli_repertoire(?string $rep): string {
 	if ($rep === '' || $rep === null) {
 		return '';
 	}