Thanks for your answer ! Sorry for the silly question, but how can I overwrite authenticate() method of the form login authentication process?

same as for onAuthenticationSuccess
see https://symfony.com/doc/current/security/custom_authenticator.html#security-passports

Not really, to use the form login authentication, success_handler is defined as an handler in the firewall config.

firewalls:
    main:
        form_login:
            success_handler: App\Security\User\Authentication\Handler\AuthenticationSuccessHandler
            ...

Have you created a custom authentication method to implement the behavior like this?

    firewalls:
        main:
            custom_authenticators:
                - App\Security\ApiKeyAuthenticator

oh yes it's a custom authenticator ;)

Ok, thanks. Sorry to bother you, but after reading the documentation several times today, I really don't understand how to create a custom authentication based on the form loging authentication. The custom_authenticators expect only a class, and form_login has a lot of options I would like to use the same way. My first idea was to extend Symfony FormLoginAuthenticator but I don't understand how to define options in the firewall config.

Perhapas you could help me showing a part of your firewall config?