diff --git a/test/test_option_with_special_name.py b/test/test_option_with_special_name.py
index 9adaf33..b2bf376 100644
--- a/test/test_option_with_special_name.py
+++ b/test/test_option_with_special_name.py
@@ -45,16 +45,8 @@ def test_root_config_answers_ok():
     assert cfg.boolop  == True
 
 def test_optname_shall_not_start_with_numbers():
-    "if you hide the root config, the options in this namespace behave normally"
-    gcdummy = BoolOption('123dummy', 'dummy', default=False)
-    boolop = BoolOption('boolop', 'Test boolean option op', default=True)
-    descr = OptionDescription('tiramisu', '', [gcdummy, boolop])
-    cfg = Config(descr)
-    # FIXME devrait lever une exception NameError
-    settings = cfg.cfgimpl_get_settings()
-    settings.enable_property('hiddend') #cfgimpl_hide()
-#    assert cfg.123dummy == False
-    assert cfg.boolop  == True
+    raises(NameError, "gcdummy = BoolOption('123dummy', 'dummy', default=False)")
+    raises(NameError, "descr = OptionDescription('123tiramisu', '', [])")
 
 def test_option_has_an_api_name():
     gcdummy = BoolOption('cfgimpl_get_settings', 'dummy', default=False)
diff --git a/tiramisu/option.py b/tiramisu/option.py
index d8de012..9fc559a 100644
--- a/tiramisu/option.py
+++ b/tiramisu/option.py
@@ -41,9 +41,13 @@ for act1, act2 in requires_actions:
 name_regexp = re.compile(r'^\d+')
 
 def valid_name(name):
-    return re.match(name_regexp, name)
-
+    if re.match(name_regexp, name) is None:
+        return True
+    else:
+        return False
+#____________________________________________________________
 #
+
 class Option(HiddenBaseType, DisabledBaseType):
     """
     Abstract base class for configuration option's.
@@ -74,7 +78,8 @@ class Option(HiddenBaseType, DisabledBaseType):
                           validation of the value
         :param validator_args: the validator's parameters
         """
-
+        if not valid_name(name):
+            raise NameError("invalid name: {0} for option".format(name))
         self._name = name
         self.doc = doc
         self._requires = requires
@@ -374,6 +379,8 @@ class OptionDescription(HiddenBaseType, DisabledBaseType):
         :param children: is a list of option descriptions (including
         ``OptionDescription`` instances for nested namespaces).
         """
+        if not valid_name(name):
+            raise NameError("invalid name: {0} for option descr".format(name))
         self._name = name
         self.doc = doc
         self._children = children