On with avoir verbs

Question

It would be useful for this lesson to point out that the issue of agreement only arises with être verbs (and the passive voice). No question arises for example with "Hier, on a quitté le travail plus tôt."

Accepted Answer

Hi Rob and Chris,
Actually this is incorrect, the rules of agreement of the past participle with 'avoir' will apply to 'on' too if the direct object precedes the verb.
Here are some examples:
Les enfants qu'on a quittés... = The children that we left...
La décision qu'on a prise = The decision which was taken/ that we took
Les bêtises qu'on a faites =The mistakes we made
etc.

Answer

Agreed. Would be good to mention that in the lesson, too.

Answer

This lesson is about agreement of the past participle when used with a compound tense with "on" when the speaker is a member of the group (and not about agreement in general), so I think that if such agreement only happens with être, then the lesson should say so. It's unclear whether this rule should be followed or not with avoir, although the fact that the only examples use être implies that it doesn't apply to avoir.

Answer

In the spirit of being absolutely precise, the original question was about subject and past participle agreement. And in that case, Rob was correct. With avoir, the past particle does not agree with the subject, ever.

What Cécile is talking about is with avoir, the past participle always agrees with a preceding direct object, if there is one. This is a separate issue from subject/past participle agreement.