In French, when we use past participles, they need to match the subject in gender (like male or female) and number (singular or plural) in some situations. Here are the main rules to keep in mind:

1. Basic Agreement:

   • If we use the helper verb être, the past participle has to match the subject in gender and number.
     • For example: Elle est allée means "She went." Here, allée matches Elle.
     • Another example: Ils sont allés means "They went." Here, allés matches Ils.

2. With avoir:

   • When using the helper verb avoir, the past participle only matches if there is a direct object that comes before it.
     • For example: J'ai mangé la pomme translates to "I ate the apple." There’s no agreement here because there’s no direct object before the verb.
     • Example with agreement: In Les pommes que j'ai mangées, which means "The apples that I ate," the past participle mangées agrees with les pommes because it is there before the verb.

3. Compound Tenses:

   • In compound tenses, it’s important to know if the past participle should match.
   • Remember these endings:
     • If the noun is feminine singular, add an -e.
     • For masculine plural, add an -s.
     • And for feminine plural, add -es.

By getting the hang of these rules, using past participles in French will be much easier!