diff --git a/apps/files/lib/Helper.php b/apps/files/lib/Helper.php
index 699caec59eb72..5ed11bd866342 100644
--- a/apps/files/lib/Helper.php
+++ b/apps/files/lib/Helper.php
@@ -217,7 +217,7 @@ public static function getFiles($dir, $sortAttribute = 'name', $sortDescending =
 	 * @param ITagManager $tagManager
 	 * @return array file list populated with tags
 	 */
-	public static function populateTags(array $fileList, $fileIdentifier = 'fileid', ITagManager $tagManager) {
+	public static function populateTags(array $fileList, $fileIdentifier, ITagManager $tagManager) {
 		$ids = [];
 		foreach ($fileList as $fileData) {
 			$ids[] = $fileData[$fileIdentifier];