The passive voice
As in English, the auxiliary used to form the passive voice is the form “to be”, which is être, colored dark red here as in an earlier post to distinguish it from both the regular verb être and the auxiliary être. In a way, it’s actually false to distinguish between the passive auxiliary être and the full verb être because both really behave the same way, including the question of requiring gender and number agreement of the adjective. The only reason, perhaps, to make this artificial distinction is to be clear that the passive auxiliary être takes as its adjective a past participle of the main verb.
That’s right: the structure of the passive voice is identical to the structure of the compound tenses using the non-modal auxiliary être. Talk about a recipe for confusion!
Except not really. Because the verbs we’ve seen so far that take être as their auxiliary are all intransitive verbs—they lack a direct object, and so there is simply no way they can form a passive at all. What this means is that it’s only really verbs taking avoir as their auxiliary that will form the passive with être.
And of course, once the passive is formed, it can form its own compound tenses. Since the conjugated verb in the passive voice is être, this means the auxiliary constructions will be formed with avoir + été + past participle (inflected).
So let’s take the sentence “I read a book” and look at every single possible verbal construction. This list will look slightly different from the list above because there I classified the verbs into seven groups based on the TAM in which the conjugated verb was conjugated. Here, though, I will be classifying them into the fourteen possibilities that we get by including the various compound tenses.