diff --git a/neutron/api/extensions.py b/neutron/api/extensions.py
index c34188f466..5919d83965 100644
--- a/neutron/api/extensions.py
+++ b/neutron/api/extensions.py
@@ -567,8 +567,7 @@ class ExtensionManager(object):
         LOG.info(_('Loaded extension: %s'), alias)
 
         if alias in self.extensions:
-            raise exceptions.Error(_("Found duplicate extension: %s") %
-                                   alias)
+            raise exceptions.DuplicatedExtension(alias=alias)
         self.extensions[alias] = ext
 
 
diff --git a/neutron/common/exceptions.py b/neutron/common/exceptions.py
index cb004a9cf6..df49df8580 100644
--- a/neutron/common/exceptions.py
+++ b/neutron/common/exceptions.py
@@ -301,3 +301,7 @@ class NetworkVlanRangeError(NeutronException):
 
 class NetworkVxlanPortRangeError(NeutronException):
     message = _("Invalid network VXLAN port range: '%(vxlan_range)s'")
+
+
+class DuplicatedExtension(NeutronException):
+    message = _("Found duplicate extension: %(alias)s")