Breakdown of Les robes que vous avez fait resserrer sont parfaites.
être
to be
parfait
perfect
vous
you (plural/formal)
avoir
to have
Questions & Answers about Les robes que vous avez fait resserrer sont parfaites.
Why is it fait and not faites, since the preceding direct object is the feminine plural Les robes?
This is the exact exception for the causative faire! Normally, a past participle in the passé composé agrees with a preceding direct object. However, when faire is immediately followed by an infinitive like resserrer to mean 'to have something done', its past participle fait never changes. It is always invariable.
How does the phrase avez fait resserrer exactly translate to 'had tightened'?
This sentence uses the causative construction, which pairs the verb faire with an infinitive. It expresses that you caused an action to happen rather than performing it yourself. Therefore, vous avez fait resserrer translates to 'you had [them] tightened' or 'you got [them] taken in' by someone else, such as a tailor.
Why does parfaites have an -es at the end if fait is invariable?
The word parfaites is an adjective describing the main subject of the sentence, Les robes. Because robe is a feminine noun and is plural here, the adjective must agree by adding an -e and an -s. The strict invariable rule only applies to the past participle fait when used in the causative structure.
Could I just use serrer instead of resserrer for 'tighten' here?