the lesson says: To express after + -ing / after having + past participle in French, you use the same following structure:
après + Infinitif passé (= infinitive of auxiliary (être or avoir) + past participleATTENTION:
Use the same auxiliary as in compound tenses like Le Passé Composé.
But all the examples are using avoir. Could you expand a little about using être in this situation? Thanks!