Unable to pull a repo via ssh

I’m trying to use ssh for pulling a repo on a dev server, but my gitlab server ask me for the git’s user password.
I’ve correctly added my public key to the gitlab server through the panel, and the ssh connexion via ssh -v git@server.tld works fine.
Then I don’t understand why my gitlab server refuse to use the publickey auth when using a git command whereas it works fine using ssh command : http://sprunge.us/LdTQ ?!

Any ideas ?