diff --git a/system/src/Grav/Common/Page/Page.php b/system/src/Grav/Common/Page/Page.php
index 43e1d0573..fd9b04d89 100644
--- a/system/src/Grav/Common/Page/Page.php
+++ b/system/src/Grav/Common/Page/Page.php
@@ -2902,7 +2902,7 @@ class Page
         $case_insensitive = Grav::instance()['config']->get('system.force_lowercase_urls');
 
         if ($case_insensitive) {
-            return strtolower($route);
+            return mb_strtolower($route);
         } else {
             return $route;
         }