diff --git a/moulinette/interfaces/api.py b/moulinette/interfaces/api.py
index 0b333e90..4bb4ef41 100644
--- a/moulinette/interfaces/api.py
+++ b/moulinette/interfaces/api.py
@@ -207,8 +207,7 @@ class _HTTPArgumentParser(object):
         return self._parser.dequeue_callbacks(*args, **kwargs)
 
     def _error(self, message):
-        # TODO: Raise a proper exception
-        raise MoulinetteError(message, raw_msg=True)
+        raise MoulinetteValidationError(message, raw_msg=True)
 
 
 class _ActionsMapPlugin(object):