diff --git a/portail_citoyen/apps/msp/views.py b/portail_citoyen/apps/msp/views.py
index c699893..d1f8494 100644
--- a/portail_citoyen/apps/msp/views.py
+++ b/portail_citoyen/apps/msp/views.py
@@ -257,7 +257,21 @@ class AuthorizeView(View):
             url = urlparse.urlunparse(parsed)
             return HttpResponseRedirect(url)
         if 'error' in GET:
-            assert False
+            assert 'state' in GET
+            state = GET['state']
+            saved = cache.get('msp-state-' + state)
+            old_state = saved['state']
+            redirect_uri = saved['redirect_uri']
+            parsed = urlparse.urlparse(redirect_uri)
+            params = urlparse.parse_qs(parsed.query)
+            params.update(dict(GET))
+            if old_state:
+                params['state'] = old_state
+            else:
+                del params['state']
+            parsed = parsed._replace(query=urllib.urlencode(params, True))
+            url = urlparse.urlunparse(parsed)
+            return HttpResponseRedirect(url)
         else:
             assert 'redirect_uri' in GET
             assert 'scope' in GET