diff --git a/address.py b/address.py
index 3200bc1cf4..0f39bcea3a 100644
--- a/address.py
+++ b/address.py
@@ -36,8 +36,9 @@ class Address(Model):
         Check validity of SIRET
         '''
         for address in self.browse(ids):
-            if address.siret and not luhn.validate(address.siret):
-                return False
+            if address.siret:
+                if len(address.siret) != 14 or not luhn.validate(address.siret):
+                    return False
         return True
 
 Address()
diff --git a/party.py b/party.py
index d9a34e6dac..64b68f851b 100644
--- a/party.py
+++ b/party.py
@@ -26,8 +26,10 @@ class Party(Model):
         Check validity of SIREN
         '''
         for party in self.browse(ids):
-            if party.siren and not luhn.validate(party.siren):
-                return False
+            if party.siren:
+                if len(party.siren) != 9 or not luhn.validate(party.siren):
+                    return False
+            print party.addresses
         return True
 
 Party()