Lequel, Auquel, Duquel: Compound Relative Pronouns Demystified

You’ve mastered qui, que and dont — then French throws « la raison pour laquelle » at you. Meet the compound relatives: lequel and its contractions. They look intimidating; they’re actually just agreement + arithmetic.

When you need them: after a preposition

Whenever the relative clause starts with a preposition (sur, dans, avec, pour, sans…), plain que won’t do — you need lequel, agreed with the noun:

• la table sur laquelle j’ai posé les clés — the table ON WHICH…
• le projet pour lequel je travaille — the project FOR WHICH…
• les raisons pour lesquelles je pars — the reasons WHY (French says “for which”!)

The four base forms

The arithmetic: à and de melt in

Exactly like à + le = au, the prepositions fuse: à + lequel = auquel, à + lesquels = auxquels, de + lequel = duquel, de + lesquelles = desquelles (laquelle resists: à laquelle, de laquelle). « Le problème auquel je pense » — the problem I’m thinking about (penser à!).

Two mercies

• People prefer qui: after a preposition with a person, French likes avec qui, pour qui: l’amie avec qui je voyage. Lequel works but sounds stiff.
• Dont beats duquel: when de belongs directly to the verb, use dont: le livre dont je parle — never « duquel je parle ». Duquel survives mainly after compound prepositions: à côté duquel, au milieu desquels.

FAQ

Isn’t lequel also a question word?

Yes — same forms, different job: Lequel tu préfères ? (Which one do you prefer?) The relative use just recycles them after prepositions.

How do I say « the day when »?

Not with lequel — French uses où for time: le jour où on s’est rencontrés. Où also covers places, saving you dans laquelle: la ville où j’habite.

Do I really need these at A2/B1?

Recognition first, production later — they’re everywhere in written French. Start producing pour lequel/laquelle (reasons) and auquel (penser à); the rest follows at B2.

Drill all the forms on the compound relatives chart, with the basics on the relative pronouns chart and question-word lequel in asking questions.

Quick practice