diff --git a/src/Wallabag/CoreBundle/Controller/ConfigController.php b/src/Wallabag/CoreBundle/Controller/ConfigController.php
index 49d909e3d..fdf3b1dc0 100644
--- a/src/Wallabag/CoreBundle/Controller/ConfigController.php
+++ b/src/Wallabag/CoreBundle/Controller/ConfigController.php
@@ -668,7 +668,7 @@ class ConfigController extends AbstractController
      */
     public function setLocaleAction(Request $request, ValidatorInterface $validator, $language = null)
     {
-        $errors = $validator->validate($language, (new LocaleConstraint()));
+        $errors = $validator->validate($language, (new LocaleConstraint(['canonicalize' => true])));
 
         if (0 === \count($errors)) {
             $request->getSession()->set('_locale', $language);
diff --git a/src/Wallabag/CoreBundle/Helper/ContentProxy.php b/src/Wallabag/CoreBundle/Helper/ContentProxy.php
index 52dcd8af0..b884b0d46 100644
--- a/src/Wallabag/CoreBundle/Helper/ContentProxy.php
+++ b/src/Wallabag/CoreBundle/Helper/ContentProxy.php
@@ -98,7 +98,7 @@ class ContentProxy
 
         $errors = $this->validator->validate(
             $value,
-            (new LocaleConstraint())
+            (new LocaleConstraint(['canonicalize' => true]))
         );
 
         if (0 === \count($errors)) {