diff --git a/sql/structure.sql b/sql/structure.sql
index f0deb42b9b52294259fee60dc1f42d54e385b8cb..8e1d90e32bdc0bedde3005dc670ef85e7919066b 100755
--- a/sql/structure.sql
+++ b/sql/structure.sql
@@ -226,7 +226,7 @@ CREATE TABLE users
   picture text,
   enabled boolean DEFAULT TRUE,
   mode character varying(50) NOT NULL,
-  preferences jsonb NOT NULL DEFAULT '{"writingMode" : "direct", "writingSize" : 1, "writingColor" : "#000000", "notifications" : true}',
+  preferences jsonb NOT NULL DEFAULT '{"lang" : "fr", "writingMode" : "direct", "writingSize" : 1, "writingColor" : "#000000", "notifications" : true}',
   cookie_key character varying(255) DEFAULT NULL::character varying,
   cookie_date timestamp without time zone,
   password_modification_date timestamp without time zone DEFAULT CURRENT_TIMESTAMP,
diff --git a/src/app/user/controllers/UserController.php b/src/app/user/controllers/UserController.php
index 5aa8b5779b26f84a61a424a1443837db4109432d..734074eb9a76c5fec58b090699deebdef515215d 100755
--- a/src/app/user/controllers/UserController.php
+++ b/src/app/user/controllers/UserController.php
@@ -132,6 +132,7 @@ class UserController
         }
 
         $check = Validator::arrayType()->notEmpty()->validate($body['preferences']);
+        $check = $check && Validator::stringType()->notEmpty()->validate($body['preferences']['lang']) && in_array($body['preferences']['lang'], ['fr', 'en']);
         $check = $check && Validator::stringType()->notEmpty()->validate($body['preferences']['writingMode']);
         $check = $check && Validator::intType()->notEmpty()->validate($body['preferences']['writingSize']);
         $check = $check && Validator::stringType()->notEmpty()->validate($body['preferences']['writingColor']);
@@ -362,7 +363,7 @@ class UserController
             $user['picture'] = 'data:image/png;base64,' . $user['picture'];
         }
 
-        $user['preferences'] = (array)json_decode($user['preferences']);
+        $user['preferences'] = json_decode($user['preferences'], true);
         $user['canManageRestUsers'] = UserController::hasPrivilege(['userId' => $args['id'], 'privilege' => 'manage_rest_users']);
 
         return $user;