diff --git a/gstlal-inspiral/bin/gstlal_ll_inspiral_event_uploader b/gstlal-inspiral/bin/gstlal_ll_inspiral_event_uploader
index 9e1fc22184891a1cc7c1b51b753a3b3dd03fb99a..5583ab023b813ac9e1051dda25767e885ef2ea80 100755
--- a/gstlal-inspiral/bin/gstlal_ll_inspiral_event_uploader
+++ b/gstlal-inspiral/bin/gstlal_ll_inspiral_event_uploader
@@ -107,7 +107,7 @@ class EventUploader(events.EventProcessor):
 			request_timeout=options.request_timeout,
 			num_messages=options.num_jobs,
 			kafka_server=options.kafka_server,
-			input_topic="gstlal.{options.tag}.{options.input_topic}",
+			input_topic=f"gstlal.{options.tag}.{options.input_topic}",
 			tag=options.tag
 		)