Hi Laurent,
I'm sorry but I'm not really understanding the issue. Can you elaborate and provide more information on the issue? Perhaps some screenshots would help? Thanks.

Hello, sorry i would like to disable the login url that the public can't access to it

http://i.imgur.com/uNNNHMn.png

Thanks

It is not possible to disable that currently but you can add some hacks in /components/com_easyblog/views/login/view.html.php to redirect requests to this page to a different url.