Passé Composé of être

Question

I thought Etre is typically imparfait because it expresses a state of being or background information.   "L'accueil du public a été bouleversant."  Why is this verb in this sentence PC? Merci!

Accepted Answer

You are correct that être, being a verb of state, is mostly used in imperfect tense when talking about the past. A state, after all, is something that has a duration, a temporal extent.
But when you use être to refer to a "point" event in the past, you use it in the passé composé. The example talks about the reception of the public, which the speaker regards as a point event and hence uses the passé composé.