diff --git a/attributs.py b/attributs.py
index 26d2ad8..60424c0 100644
--- a/attributs.py
+++ b/attributs.py
@@ -126,7 +126,7 @@ def attrify(val, attr, conn, Parent=None):
         return val
     else:
         attr_classe = AttributeFactory.get(attr, fallback=Attr)
-        if not isinstance(val, unicode) and (attr_classe.python_type and not isinstance(val, attr_classe.python_type)):
+        if not isinstance(val, unicode) and not (attr_classe.python_type and isinstance(val, attr_classe.python_type)):
             cranslib.deprecated.usage("attrify ne devrait être appelé qu'avec des unicode (%r)" % val, level=3)
             val = val.decode('utf-8')
         return attr_classe(val, conn, Parent)