diff --git a/neutron/db/db_base_plugin_v2.py b/neutron/db/db_base_plugin_v2.py
index 8f492263007..6a4a64ef2d7 100644
--- a/neutron/db/db_base_plugin_v2.py
+++ b/neutron/db/db_base_plugin_v2.py
@@ -455,6 +455,11 @@ class NeutronDbPluginV2(db_base_plugin_common.DbBasePluginCommon,
                 network = self._make_network_dict(network_db, context=context)
                 registry.notify(resources.NETWORK, events.PRECOMMIT_DELETE,
                                 self, context=context, network_id=id)
+                # We expire network_db here because precommit deletion
+                # might have left the relationship stale, for example,
+                # if we deleted a segment.
+                context.session.expire(network_db)
+                network_db = self._get_network(context, id)
                 context.session.delete(network_db)
         registry.notify(resources.NETWORK, events.AFTER_DELETE,
                         self, context=context, network=network)
diff --git a/neutron/services/segments/db.py b/neutron/services/segments/db.py
index b71fda7c81f..ef383d03cde 100644
--- a/neutron/services/segments/db.py
+++ b/neutron/services/segments/db.py
@@ -314,6 +314,6 @@ def subscribe():
                        resources.SEGMENT, events.PRECOMMIT_CREATE)
     registry.subscribe(_delete_segments_for_network,
                        resources.NETWORK,
-                       events.BEFORE_DELETE)
+                       events.PRECOMMIT_DELETE)
 
 subscribe()
diff --git a/neutron/tests/unit/extensions/test_segment.py b/neutron/tests/unit/extensions/test_segment.py
index 9c48b63ae08..fcb6d9f27b7 100644
--- a/neutron/tests/unit/extensions/test_segment.py
+++ b/neutron/tests/unit/extensions/test_segment.py
@@ -356,6 +356,18 @@ class TestSegment(SegmentTestCase):
             self._update('segments', segment['segment']['id'], segment,
                          expected_code=webob.exc.HTTPClientError.code)
 
+    def test_segment_notification_on_delete_network(self):
+        with mock.patch.object(db, '_delete_segments_for_network') as dsn:
+            db.subscribe()
+            with self.network() as network:
+                network = network['network']
+                self._delete('networks', network['id'])
+        dsn.assert_called_with(resources.NETWORK,
+                               events.PRECOMMIT_DELETE,
+                               mock.ANY,
+                               context=mock.ANY,
+                               network_id=mock.ANY)
+
 
 class TestSegmentML2(SegmentTestCase):
     def setUp(self):