Complex Relative Pronouns: Auquel, Duquel and Related Forms

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You already know qui, que, dont and où. They handle most of what French throws at you. But some verbs require a preposition — sur, avec, pour, par, sans — and when the antecedent is a thing rather than a person, none of the four simple pronouns can follow it. French solves this with lequel and its forms.

In this post

1. When the simple pronouns aren't enough
2. The forms of lequel
3. Contractions with à and de
4. Dont or duquel?
5. Lequel with people

When the simple pronouns aren't enough

The four simple relative pronouns cover most everyday situations. But they have a blind spot: they can't follow a preposition that is required by the verb or expression in the relative clause, unless that preposition happens to be de, which is handled by dont.

So what happens with all the other prepositions: sur, avec, pour, par, sans, dans, à...?

The problem

Take two sentences and try to connect them:

C'est le projet. (This is the project.)

Nous travaillons sur ce projet. (We are working on this project.)

❌  C'est le projet qui...  — the project isn't the subject of travailler

❌  C'est le projet que...  — travailler sur is not a direct object construction

❌  C'est le projet dont...  — the preposition is sur, not de

❌  C'est le projet où...  — not a place or time reference

✓  C'est le projet sur lequel nous travaillons. (This is the project we are working on.)

The core principle

When a verb or expression requires a preposition, and the antecedent is a thing, an animal, or an abstract idea, place that preposition directly before the appropriate form of lequel.

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The forms of lequel

Lequel is the only relative pronoun that varies for gender and number. It agrees with the noun it refers back to (its antecedent).

	Masculine	Feminine
Singular	lequel	laquelle
Plural	lesquels	lesquelles

Examples

L'entreprise pour laquelle nous travaillons va ouvrir une nouvelle usine en Inde. (The company we work for is going to open a new factory in India.)

Le voisin avec lequel je parlais quitte la région. (The neighbour I was talking to is leaving the area.)

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Contractions with à and de

When the required preposition is à or de, lequel forms contract, following the same pattern as the definite article. Laquelle never contracts. Only the masculine singular and both plural forms do.

With à

à + lequel → auquel

à + lesquels → auxquels

à + lesquelles → auxquelles

à + laquelle → à laquelle (no contraction)

With de

de + lequel → duquel

de + lesquels → desquels

de + lesquelles → desquelles

de + laquelle → de laquelle (no contraction)

Examples

Paul a adopté Spencer dans un refuge de Ballarat. C’est un chien auquel il tient énormément. (Paul adopted Spencer from a shelter in Ballarat. Spencer is a dog he cares deeply about.)

C’est une question à laquelle je n’ai pas de réponse. (This is a question for which I have no answer.)

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Dont or duquel / de laquelle?

If de is the required preposition, you might wonder: isn't that exactly what dont already handles? The answer is: sometimes yes, sometimes no.

Use dont

When de is attached directly to the verb, adjective, or noun in the clause:

parler de, avoir besoin de, être fier de, le résultat de...

Use duquel / de laquelle

When de is part of a compound preposition that must stay intact:

en face de, à côté de, au bord de, près de, au bout de, à cause de...

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Why can't dont replace a compound preposition?

Dont can only absorb a simple de attached to a verb or noun. A compound preposition like en face de functions as a single unit. If you used dont, you'd be left with an orphaned en face, which makes no sense. The compound must stay intact, which means you need a lequel form to carry the de.

Dont

C’est un auteur dont j’admire beaucoup le travail. (He is an author whose work I greatly admire.)

Admirer le travail de quelqu’un — the de belongs directly to the noun phrase le travail de. Dont absorbs it cleanly.

Compound preposition → de laquelle / duquel

Tu connais la boulangerie Berthot ? C’est celle en face de laquelle je vis. (You know Berthot’s bakery? That’s the one I live opposite.)

En face de is a compound preposition that functions as a single unit. Dont can only replace a simple de attached to a verb or noun. Using dont here would leave an orphaned en face, which means nothing on its own. The compound must stay intact, so de laquelle carries the de.

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Lequel with people

After most prepositions, qui is the standard choice for people. Lequel forms are grammatically correct alternatives, and occasionally preferred in formal writing where the gender and number agreement helps identify the antecedent more precisely. But in everyday usage, qui is simpler and more natural.

In practice

Both are correct. Qui is preferred in speech and informal writing.

Examples

C’est un médecin à qui je fais entièrement confiance. (This is a doctor I trust completely.)

C’est un médecin auquel je fais entièrement confiance. (same meaning, more formal register)

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The principle is consistent: identify the preposition the verb requires, determine the gender and number of the antecedent, and the form follows. The contractions with à and de behave exactly like those of the definite article. The dont / duquel distinction rests on one question: is de attached directly to the verb, or is it part of a compound preposition? Answer that, and the choice is clear.

→ New to relative pronouns? Start with Simple Relative Pronouns: Qui, Que, Dont, Où

→ Ready to practise? Five exercises on lequel and its forms