nginx - client_max_body_size has no effect

nginx keeps saying `client intended to send too large body`. Googling and RTM pointed me to `client_max_body_size`. I set it to `200m` in the `nginx.conf` as well as in the `vhost conf`, restarted Nginx a couple of times but I'm still getting the error message. Did I overlook something? The backend is `php-fpm` (`max_post_size` and `max_upload_file_size` are set accordingly).