You already know that the passé composé is built with two parts: an auxiliary verb (either avoir or être in the present tense) and the past participle of the main verb. It's the go-to tense for talking about completed actions in the past. Most verbs pair with avoir, like in J'ai mangé une pomme (I ate an apple).

A smaller, specific group of verbs uses être. This is where things get interesting, because être introduces a new rule: agreement.

Think of the past participle as a chameleon. Most of the time, it stays one color, like in J'ai mangé, tu as mangé, elle a mangé. The participle mangé never changes. But in certain situations, it changes its form to match the gender and number of another word in the sentence, just like an adjective would.

Verbs that use être as their auxiliary are mostly verbs of motion or a change of state. A popular mnemonic to remember them is DR MRS VANDERTRAMP.

• Devenir (to become)
• Revenir (to come back)
• Monter (to go up)
• Rester (to stay)
• Sortir (to go out)
• Venir (to come)
• Aller (to go)
• Naître (to be born)
• Descendre (to go down)
• Entrer (to enter)
• Rentrer (to return)
• Tomber (to fall)
• Retourner (to turn around)
• Arriver (to arrive)
• Mourir (to die)
• Partir (to leave)

When you use any of these verbs in the passé composé, the past participle must agree with the subject. Add an -e for a feminine subject, an -s for a plural subject, and -es for a feminine plural subject.

All reflexive verbs also use être and follow the same agreement rule with the subject. For example, Elle s'est levée (She got up).

Normally, past participles with avoir don't agree with anything. But there's one major exception: when a direct object pronoun comes before the verb.

Look at this sentence: J'ai vu la voiture. (I saw the car). The past participle vu doesn't change.

Now, let's replace "la voiture" with a direct object pronoun. Since voiture is feminine, the pronoun is la. It goes before the auxiliary verb: Je l'ai vue. (I saw it). Notice the change? The past participle vu becomes vue to agree with la (which represents la voiture).

This rule applies to all direct object pronouns: me, te, le, la, nous, vous, les. The key is their placement before the verb.

This concept of agreement is a core part of mastering French past tenses. It might seem tricky at first, but with practice, spotting when to add that extra -e or -s will become second nature.