No native speaker but I think fété does not exist. The corrected form is fête. The corresponding verb is fêter whose past participle is fêté. May be it is the last one that you have seen.

Like Dimitris said "fête" could mean anything like holiday, party, celebration that you could relate to "festival" or "feast" in English, as for "fété", it is the past participle (participe passé) of the verb "fêter" which basically means celebrate or observe e.g: Hier, il a fêté son anniversaire (he celebrated his birthday yesterday) or les Chrétiens fètent Noël (Christians celebrate or observe Christmas).