diff --git a/examples/cloud_run_event/Dockerfile b/examples/cloud_run_event/Dockerfile
index 6b31c042..b3e7ffeb 100644
--- a/examples/cloud_run_event/Dockerfile
+++ b/examples/cloud_run_event/Dockerfile
@@ -12,4 +12,4 @@ RUN pip install gunicorn functions-framework
 RUN pip install -r requirements.txt
 
 # Run the web service on container startup.
-CMD exec functions-framework --target=hello --signature_type=event
+CMD exec functions-framework --target=hello --signature-type=event