Language/French/Grammar/Pronominal-Verbs-Agreement

Accord of pronominal verbs :

Essentially pronominal verbs, that is to say that exist only in pronominal form (with "se" in infinitive forme), are always accorded in gender and number with the subject.

exemple : Elle s'est souvenue de vous.

Occasionally pronominal verbs i.e. that exist in non-pronominal form, are accorded as a past participle like with the auxiliary "avoir". That is to say with the complement (COD) of the sentence if the complement is before the verb. If it's not the case, the verb isn't accorded.

exemples : Ils se sont échangés des lettres.

Les lettre qu'ils se sont échangées.