diff --git a/site/controllers/notes.php b/site/controllers/notes.php
index 2063568..0180e91 100644
--- a/site/controllers/notes.php
+++ b/site/controllers/notes.php
@@ -11,7 +11,7 @@
  */
 return function ($page) {
 
-    $tag   = urldecode(param('tag'));
+    $tag   = urldecode(param('tag') ?? '');
     /**
      * We use the collection helper to fetch the notes collection defined in `/site/collections/notes.php`
      *