The agreement of past participle in case of DOP

Bonjour Trupti,

Here is a link that addresses part of your question: reflexive-verbs-in-the-passe-compose-conversational-past

Also, there is agreement with the pronouns ‘me, te, nous, vous’ if the pronoun is a direct object of the verb.

Les enfants ? Vous nous avez entendus ? = Children ? Did you hear us?

→ whom did you hear ? → ‘nous’ = ‘us’ = direct object → agreement

Here is another link (although it is more about the position of the pronouns) for you to look at as there are a few examples as mentioned above

I hope this is helpful.

Bonne journée !