diff --git a/grandlyon/scripts/generate-geojson.py b/grandlyon/scripts/generate-geojson.py
index d14bfd1..f0e752f 100644
--- a/grandlyon/scripts/generate-geojson.py
+++ b/grandlyon/scripts/generate-geojson.py
@@ -31,6 +31,7 @@ for formdef in FormDef.select():
         for field in ('numero', 'voie', 'commune', 'message', 'type_probleme'):
             feature['properties'][field] = formdata_vars.get('form_var_%s' % field)
         feature['properties']['datetime'] = formdata_vars['form_receipt_datetime'].strftime('%d/%m/%Y %H:%M')
+        feature['properties']['reference'] = '%s:%s' % (formdata_vars['form_slug'], formdata_id)
 
     json.dump(geojson, open(os.path.join(geojson_dir, formdef.url_name + '.json'), 'w'),
             indent=2, cls=JSONEncoder)