diff --git a/lib/public/Common/Exception/NotFoundException.php b/lib/public/Common/Exception/NotFoundException.php
index 309efe3e220..a2cd4db8634 100644
--- a/lib/public/Common/Exception/NotFoundException.php
+++ b/lib/public/Common/Exception/NotFoundException.php
@@ -35,7 +35,7 @@ class NotFoundException extends \Exception {
 	 * @param string $msg the error message
 	 * @since 28.0.0
 	 */
-	public function __construct($msg) {
+	public function __construct(string $msg) {
 		parent::__construct($msg);
 	}
 }