diff --git a/src/jcl/error.py b/src/jcl/error.py
index 5bf3ced..778343e 100644
--- a/src/jcl/error.py
+++ b/src/jcl/error.py
@@ -29,21 +29,23 @@ from jcl.lang import Lang
 class FieldError(Exception):
     """Error raised when error exists on Jabber Data Form fields"""
 
-    def __init__(self, field, message="", message_property=None, lang_class=Lang.en):
+    def __init__(self, field,
+                 message_property=None, lang_class=Lang.en,
+                 detailed_message=None):
         Exception.__init__(self)
         self.field = field
         self.lang_class = lang_class
         self.message_property = message_property
-        self.message = message
+        self.detailed_message = detailed_message
 
     def __str__(self):
-        if self.message_property is None \
-                or not hasattr(self.lang_class, self.message_property):
-            return self.lang_class.field_error % (str(self.field), self.message)
-        else:
-            return self.lang_class.field_error % \
-                (str(self.field),
-                 str(getattr(self.lang_class, self.message_property)))
+        full_message = ""
+        if self.detailed_message is not None:
+            full_message = self.detailed_message
+        elif self.message_property is not None \
+                and hasattr(self.lang_class, self.message_property):
+            full_message = str(getattr(self.lang_class, self.message_property))
+        return self.lang_class.field_error % (str(self.field), full_message)
 
 class MandatoryFieldError(FieldError):
     """Error raised when a mandatory field in a Form is not supplied"""
@@ -54,5 +56,7 @@ class MandatoryFieldError(FieldError):
 class NotWellFormedFieldError(FieldError):
     """Error raised when a supplied field in a Form is not well formed"""
 
-    def __init__ (self, field):
-        FieldError.__init__(self, field, message_property="not_well_formed_field")
+    def __init__ (self, field, detailed_message=None):
+        FieldError.__init__(self, field,
+                            message_property="not_well_formed_field",
+                            detailed_message=detailed_message)
diff --git a/src/jcl/jabber/register.py b/src/jcl/jabber/register.py
index 4c24bcc..160050c 100644
--- a/src/jcl/jabber/register.py
+++ b/src/jcl/jabber/register.py
@@ -70,7 +70,8 @@ class SetRegisterHandler(object):
                 info_query, lang_class)
         if not self.field_name_regexp.match(form["name"].value):
             return self.handle_error(\
-                    NotWellFormedFieldError("name"),
+                    NotWellFormedFieldError("name",
+                                            lang_class.arobase_in_name_forbidden),
                     info_query, lang_class)
         return None
 
diff --git a/src/jcl/lang.py b/src/jcl/lang.py
index 9fb79cb..5a5ccd0 100644
--- a/src/jcl/lang.py
+++ b/src/jcl/lang.py
@@ -92,6 +92,7 @@ class Lang:
         field_error = u"Error with '%s' field: %s"
         mandatory_field = u"required field"
         not_well_formed_field = u"not well formed field"
+        arobase_in_name_forbidden = u"'@' is not allowed in account's name"
 
         field_chat_action = u"Action when state is 'Free For Chat'"
         field_online_action = u"Action when state is 'Online'"
@@ -266,8 +267,10 @@ class Lang:
                                          u"à jour"
         update_account_message_body = u"Compte mis à jour"
 
+        field_error = u"Erreur dans le champs '%s': %s"
         mandatory_field = u"%s est requis"
         not_well_formed_field = u"Le champs %s n'est pas acceptable"
+        arobase_in_name_forbidden = u"Le nom du compte ne peux contenir le charactère '@'"
 
         field_chat_action = u"Action lorsque l'état est 'Free For Chat'"
         field_online_action = u"Action lorsque l'état est 'Online'"
diff --git a/src/jcl/tests/lang.py b/src/jcl/tests/lang.py
index 9a92ad0..c45d37d 100644
--- a/src/jcl/tests/lang.py
+++ b/src/jcl/tests/lang.py
@@ -94,6 +94,7 @@ class Language_TestCase(unittest.TestCase):
         self.assertNotEquals(self.lang_class.field_error % ("", ""), None)
         self.assertNotEquals(self.lang_class.mandatory_field, None)
         self.assertNotEquals(self.lang_class.not_well_formed_field, None)
+        self.assertNotEquals(self.lang_class.arobase_in_name_forbidden, None)
 
         self.assertNotEquals(self.lang_class.field_chat_action, None)
         self.assertNotEquals(self.lang_class.field_online_action, None)