Enable SSLv3 in nginx on debian server

For some demonstration on HTTPS weakness, I'd like to enable SSLv3 on one sub domain of my webserver. I use nginx 1.12.2 on debian 8, and already tried to add the following line

ssl_protocols SSLv2 SSLv3 TLSv1 TLSv1.1 TLSv1.2;

and then a sudo service nginx restart, but ssllabs still shows SSL as disabled (with the clear-cache option).

Apparently the version of openssl I have supports SSLv3 (openssl ciphers -v), so I don't understand why SSLv3 isn't enabled.

Thanks !