diff --git a/debexpo/tools/clients/ftp_master.py b/debexpo/tools/clients/ftp_master.py
index 677785c3c33f0436d4554a422335e7f269ea3385..824d061dd0164c4e90eda6f7a406251f8073f9f5 100644
--- a/debexpo/tools/clients/ftp_master.py
+++ b/debexpo/tools/clients/ftp_master.py
@@ -63,6 +63,7 @@ class ClientFTPMasterAPI(ClientJsonAPI):
         params = {
             'package': package,
             's': distribution,
+            'a': 'source',
             'f': 'json'
         }