How to unlock an iPhone with Activation Lock?

It does not work that way. If you are seeing Activation Lock, then you must have your original purchase receipt from Apple or Authorized Apple seller. No other receipt will be accepted.

Is this what you are seeing and do you have that receipt?

L'activation verrouillée nécessite que vous connaissiez l'ID Apple et le mot de passe de la personne qui a configuré le téléphone à l'origine.

avez-vous cette information?