diff --git a/subcmds/sync.py b/subcmds/sync.py
index 5655a1e..f1fe88d 100644
--- a/subcmds/sync.py
+++ b/subcmds/sync.py
@@ -199,6 +199,7 @@
       self.jobs = 1
 
     p.add_option('-f', '--force-broken',
+                 dest='force_broken', action='store_true',
                  help='obsolete option (to be deleted in the future)')
     p.add_option('--fail-fast',
                  dest='fail_fast', action='store_true',