Laisser and verbs of perception + infinitive

Je laisse mon fils conduire.I let my son drive.

Laisser and verbs of perception like voir, entendre, regarder, écouter and sentir can combine directly with an infinitive — no que, no second clause — to describe letting or perceiving someone do something. This works much like faire + infinitive, but with one welcome difference: the person doing the action has more freedom about where it goes in the sentence.

Quick shortcut: laisser/voir/entendre + infinitive, no que — when the infinitive has no object of its own, the person doing the action can go either right before or right after it; once the infinitive has its own object, it goes before.

Laisser + infinitive: letting someone do something

When the infinitive has no object of its own, both of these word orders are equally correct:

• Je laisse mon fils conduire. / Je laisse conduire mon fils. (I let my son drive.)
• Elle laisse les enfants jouer dehors. / Elle laisse jouer dehors les enfants. (She lets the children play outside.)

But once the infinitive already has its own direct object, the causee goes before the infinitive — reversing the order (infinitive, its object, then the causee) isn't a natural alternative the way it is above, so this is really the only option, not just the clearer one. This needs no à/par juggling the way faire requires, since the word order alone keeps the roles apart:

• Elle laisse son fils manger le gâteau. (She lets her son eat the cake.) — son fils (the one eating) comes right after laisser; le gâteau (what's eaten) follows the infinitive.

Verbs of perception + infinitive: voir, entendre, regarder...

Verbs of perception follow the same pattern. When the infinitive has no object, the perceived subject can go before or after it, though before is the more natural, more common choice in everyday French:

• Je vois mon frère partir. (I see my brother leaving.) — more natural than Je vois partir mon frère, though both are grammatical.
• Elle regarde le soleil se coucher. (She watches the sun set.)

But once the infinitive has its own object, the perceived subject has to come before it — J'entends chanter une chanson les enfants isn't a natural alternative to the version below:

• J'entends les enfants chanter une chanson. (I hear the children singing a song.)

Where the pronoun goes

Just like with faire, an object pronoun replacing the causee or perceived subject goes right before the conjugated verb — laisser, voir, entendre — never attached to the infinitive, even though an ordinary modal verb would put it there:

• Je laisse mon fils conduire. → Je le laisse conduire. (I let him drive.) — not Je laisse le conduire for this meaning; that sentence is grammatical, but it means something different ("I let him drive it," with le as the object of conduire instead of the person being allowed to drive).
• Je vois mon frère partir. → Je le vois partir. (I see him leaving.) — never ❌ Je vois le partir.

Past participle agreement: only when the causee does the action

In a compound tense, the past participle of a perception verb agrees with a preceding direct object — but only when that object is the one doing the infinitive's action, not when it's what the action is done to. This is the same preceding-direct-object rule you already know, with one extra wrinkle specific to this construction:

• La femme que j'ai vue sortir. (The woman I saw leave.) — agrees, because la femme is the one doing the leaving — the subject of sortir.
• La chanson que j'ai entendu chanter. (The song I heard being sung.) — no agreement, because la chanson is what's sung — the object of chanter, not the singer.

Laissé followed by an infinitive works differently: in modern French (following the 1990 spelling reform), it stays invariable no matter what, just like fait — *Je **l'*ai laissé partir (even for a feminine l'), not laissée.

Common mistakes

• ❌ J'ai vu ma sœur partie. → ✅ J'ai vu ma sœur partir. (the second verb stays an infinitive — it's never a past participle here)
• ❌ Je vois le partir. → ✅ Je le vois partir. (the pronoun goes before the conjugated verb, not attached to the infinitive)
• ❌ La chanson que j'ai entendue chanter. → ✅ La chanson que j'ai entendu chanter. (la chanson is the object of chanter, not the one singing — no agreement)

Quick check

Key takeaways

• Laisser and verbs of perception (voir, entendre, regarder, écouter, sentir) combine directly with an infinitive — no que, no separate clause — to describe letting or perceiving an action.
• Unlike faire + infinitive, the causee/perceived subject can go before or after the infinitive when it has no object of its own; once the infinitive has its own object, the causee/subject has to come before it.
• An object pronoun goes right before the conjugated verb (laisser, voir, entendre...), never attached to the infinitive.
• A perception verb's past participle agrees with a preceding direct object only when that object performs the infinitive's action — la femme que j'ai vue sortir, but la chanson que j'ai entendu chanter.
• Laissé + infinitive stays invariable in modern French, unlike the perception-verb rule above.