diff --git a/daphne/cli.py b/daphne/cli.py
index dc715a6..62aa8d3 100755
--- a/daphne/cli.py
+++ b/daphne/cli.py
@@ -226,7 +226,7 @@ class CommandLineInterface(object):
                 args.host,
                 args.port is not None,
                 args.unix_socket,
-                args.file_descriptor,
+                args.file_descriptor is not None,
                 args.socket_strings,
             ]
         ):