diff --git a/sat/core/xmpp.py b/sat/core/xmpp.py
index e8c2c46c..e932361d 100644
--- a/sat/core/xmpp.py
+++ b/sat/core/xmpp.py
@@ -971,7 +971,7 @@ class SatMessageProtocol(xmppim.MessageProtocol):
             message_elt.defaultUri = message_elt.uri = C.NS_CLIENT
             for c in message_elt.elements():
                 if c.uri is None:
-                    c.uri == C.NS_CLIENT
+                    c.uri = C.NS_CLIENT
         elif message_elt.uri != C.NS_CLIENT:
             log.warning(_(
                 u"received <message> with a wrong namespace: {xml}"