What is the difference between qui and que in French relative clauses?

Qui is the subject relative - it stands in for the subject of the clause that follows. 'L'homme qui parle' (the man who is speaking) - qui is the subject of parle. Que is the object relative - it stands in for the object. 'Le livre que je lis' (the book that I read) - que is the object, je is the subject. The split is grammatical, not semantic: qui can refer to people, things, or animals, and so can que. What matters is the role they play in the embedded clause. If a subject follows the relative pronoun, you need que; if a verb follows directly, you need qui.

When do you use 'dont' in French?

Dont replaces 'de + noun' in a relative clause. Any time the relative clause would have started with 'de' in a non-relative version, use dont. 'C'est le livre dont je parle' (this is the book I'm talking about) - because parler de quelque chose takes de. 'L'homme dont la voiture est rouge' (the man whose car is red) - because the car is OF the man, marked with de. Dont covers 'whose', 'of which', 'about which', 'from which' in English. It's a single pronoun that does a lot of work.

French Relative Pronouns

Relative pronouns connect a clause to a noun. French has four at Foundation tier: qui, que, dont, ou. Each one corresponds to a specific grammatical role in the clause it introduces.

qui: subject relative

Qui stands in for the subject of the relative clause. It can refer to people, things, or animals - what matters is its role, not its referent.

L'homme qui parle est mon pere. (The man who is speaking is my father.) - qui is the subject of parle
Le livre qui est sur la table. (The book that is on the table.) - qui is the subject of est
J'ai un ami qui habite a Tokyo. (I have a friend who lives in Tokyo.)
C'est moi qui ai fait ca. (It's me who did that.)

A useful test: if a verb follows directly with no other subject, use qui.

que: object relative

Que stands in for the direct object of the relative clause. A different subject appears after it.

Le livre que je lis. (The book that I'm reading.) - je is the subject, que is the object
L'homme que tu as vu. (The man that you saw.)
La maison que nous avons achetee. (The house that we bought.)
Le film que j'ai vu hier. (The film I saw yesterday.)

Before a vowel, que elides to qu': le livre qu'elle ecrit.

The test: if a subject follows the relative pronoun, use que.

Past-participle agreement with que

When the relative clause is in the passe compose with avoir, the past participle agrees with the preceding direct object that que refers to.

La pomme que j'ai mangee. (The apple that I ate.) - mangee agrees with feminine la pomme
Les livres que j'ai lus. (The books I read.) - lus agrees with masculine plural les livres
Les chansons qu'elle a chantees. (The songs she sang.) - chantees agrees with feminine plural

This is the avoir-agreement rule from the passe compose page firing in practice. Flagged here, not drilled - it matters most in writing.

dont: de + noun

Dont replaces any "de + noun" in a relative clause. Use it wherever the non-relative version would have started with de.

Common cases:

C'est le livre dont je parle. (This is the book I'm talking about.) - parler de quelque chose
L'homme dont la voiture est rouge. (The man whose car is red.) - the car de l'homme
Le film dont j'ai oublie le titre. (The film whose title I forgot.) - le titre du film
La maladie dont il souffre. (The illness he suffers from.) - souffrir de

English uses "whose", "of which", "about which", "from which" - French collapses all of them to dont.

The structure is rigid: dont + subject + verb + the rest. Even when the de-relation is to a possession, the possessor (with dont) comes before the thing possessed.

L'homme dont la voiture est rouge. ✓
L'homme la voiture dont est rouge. ✗

ou: place and time

Ou as a relative covers "where" and "when". Same word as the question word.

La ville ou j'habite. (The city where I live.)
Le restaurant ou nous mangeons. (The restaurant where we eat.)
Le jour ou je suis arrive. (The day I arrived.)
L'annee ou nous nous sommes rencontres. (The year we met.)

The "when" use is the one English speakers miss - English uses "when", French uses ou.

ce qui and ce que: nominal relatives

When the relative refers to "what" rather than a specific noun, French uses ce qui (subject) and ce que (object). These are the equivalent of English "what" in "I don't know what you mean".

Ce qui me plait, c'est la musique. (What I like is the music.) - ce qui is the subject
Ce que je veux, c'est partir. (What I want is to leave.) - ce que is the object
Je ne comprends pas ce que tu dis. (I don't understand what you're saying.)
Dis-moi ce qui s'est passe. (Tell me what happened.)

Same qui / que split: ce qui when followed by a verb directly, ce que when followed by a subject.

There's also ce dont: je sais ce dont tu parles (I know what you're talking about). Same de-replacement rule as dont.

lequel and friends (briefly)

After most prepositions, French uses lequel / laquelle / lesquels / lesquelles for things. These agree with the noun they refer to.

La chaise sur laquelle je suis assis. (The chair I'm sitting on.)
Les amis avec lesquels je voyage. (The friends I'm travelling with.)

For people after a preposition, French uses qui:

L'homme avec qui je parlais. (The man I was talking to.)

The full lequel system is Higher-tier on the AQA list. Recognise it; you don't have to produce it confidently at Foundation level.

Worked examples

Le garcon qui habite a cote est mon ami. (The boy who lives next door is my friend.)
C'est le film que je voulais voir. (It's the film I wanted to see.)
L'auteur dont j'ai parle hier est francais. (The author I talked about yesterday is French.)
La maison ou j'ai grandi a ete vendue. (The house where I grew up has been sold.)
Le jour ou nous sommes arrives, il pleuvait. (The day we arrived, it was raining.)
Je ne sais pas ce qu'elle veut. (I don't know what she wants.)
Dis-moi ce qui te plait. (Tell me what you like.)

Common mistakes English speakers make

Using qui for an object because the English "who" or "that" feels like it: le livre qui je lis is wrong, it's le livre que je lis. The subject is je, so the relative is que. Using quand as a relative for time: le jour quand je suis arrive is wrong, it's le jour ou je suis arrive. And dropping the relative pronoun entirely, which English allows ("the book I read") but French forbids - le livre je lis is broken; it has to be le livre que je lis.