diff --git a/phpBB/phpbb/mimetype/guesser_interface.php b/phpBB/phpbb/mimetype/guesser_interface.php
index 103689765e..3cbcfeabe3 100644
--- a/phpBB/phpbb/mimetype/guesser_interface.php
+++ b/phpBB/phpbb/mimetype/guesser_interface.php
@@ -26,6 +26,7 @@ interface guesser_interface
 	* Guess mimetype of supplied file
 	*
 	* @param string $file Path to file
+	* @param string $file_name The real file name
 	*
 	* @return string Guess for mimetype of file
 	*/