What are the French demonstrative pronouns?

Celui (masculine singular), celle (feminine singular), ceux (masculine plural) and celles (feminine plural). They all mean 'the one' or 'the ones' and replace a noun already mentioned, agreeing with it in gender and number: 'le bureau de Clara et celui de Marc' (Clara's desk and Marc's). They are different from the demonstrative adjectives ce / cet / cette / ces, which sit before a noun ('this book') rather than standing in for it ('the one').

Why can't celui stand on its own in French?

Because celui is incomplete by itself - it always needs something to specify which one. There are three legal completions: a suffix -ci or -la (celui-ci, this one; celui-la, that one), de + a noun (celui de Pierre, Pierre's one), or a relative clause (celui qui parle, the one who is speaking; celui que je veux, the one I want; celui dont je parle, the one I'm talking about). 'Je veux celui.' on its own is wrong; you must say celui-ci, celui de Marc, or celui qui...

What is the difference between celui-ci and celui-la?

The -ci / -la split is distance, exactly like the adjective suffixes. Celui-ci is 'this one' (near), celui-la is 'that one' (far): 'Quel manteau? - Celui-la.' (Which coat? That one.). The pair also does 'the latter' (celui-ci, the one just mentioned) versus 'the former' (celui-la, the one mentioned earlier). In everyday speech celui-la does most of the pointing work; the contrast only matters when you genuinely need to mark near against far.

French Demonstrative Pronouns

Demonstrative pronouns are how French says the one and the ones without repeating a noun. Instead of "Clara's desk and Marc's desk" you say le bureau de Clara et celui de Marc - the second bureau collapses into celui. The four forms agree in gender and number with the noun they stand in for, and the single rule that trips everyone up is that they never stand fully alone. celui always needs finishing off.

The four forms

Each form agrees with the noun it replaces, not with anything else in the sentence.

Gender / number	Pronoun	English
masculine singular	celui	the one
feminine singular	celle	the one
masculine plural	ceux	the ones
feminine plural	celles	the ones

celui replaces a masculine singular noun: mon vélo et celui de Paul (my bike and Paul's).
celle replaces a feminine singular noun: ma voiture et celle de Paul (my car and Paul's).
ceux replaces a masculine plural noun: mes livres et ceux de la bibliothèque (my books and the library's).
celles replaces a feminine plural noun: mes clés et celles de ma soeur (my keys and my sister's).

Don't confuse these with the demonstrative adjectives ce / cet / cette / ces, which mean "this / that" and sit in front of a noun. Those are covered on the French demonstratives page. The adjective points at a noun that is present (ce livre, this book); the pronoun stands in for a noun you have removed (celui-ci, this one).

The rule that matters: celui never stands alone

This is the whole game. You cannot say je veux celui and stop. celui is grammatically unfinished; it has to be completed by one of exactly three things. Get this and the topic is done.

1. With -ci or -la (distance and "this one / that one")

Bolt -ci (near) or -la (far) onto the pronoun with a hyphen. This is the same distance split as the demonstrative adjectives.

celui-ci (this one) / celui-la (that one)
celle-ci (this one) / celle-la (that one)
ceux-ci (these ones) / ceux-la (those ones)
celles-ci (these ones) / celles-la (those ones)

Examples:

Quel manteau préfères-tu? - Celui-la. (Which coat do you prefer? That one.)
Ces gâteaux sont bons, mais ceux-ci sont meilleurs. (These cakes are good, but these ones are better.)
Je prends celle-ci, pas celle-la. (I'll take this one, not that one.)

The same pair does the latter (celui-ci, the more recently mentioned) versus the former (celui-la, the earlier one). In ordinary speech -la carries most of the pointing, and you only reach for the -ci / -la contrast when near versus far genuinely matters.

2. With de + a noun (possession or origin)

celui de + a noun means "the one belonging to" or "the one from". This is the workhorse use - it's how French avoids repeating a noun across a possessive.

le bureau de Clara et celui de Marc (Clara's desk and Marc's)
Ma valise est plus lourde que celle de ma mère. (My case is heavier than my mother's.)
Les rues de Paris et celles de Lyon (the streets of Paris and those of Lyon)
Ce n'est pas mon problème, c'est celui de mon frère. (It's not my problem, it's my brother's.)

English does the same job with an apostrophe-s ("Marc's") or "the one from". French has no possessive apostrophe, so celui de is doing the work that 's does in English. Learn it as a unit: celui / celle / ceux / celles + de.

3. With a relative clause (qui, que, dont)

celui can be completed by a relative pronoun, picking out "the one who / that / which". The relative pronoun you choose follows the normal rules from the relative pronouns page.

celui qui parle (the one who is speaking) - qui is the subject of the clause.
celui que je veux (the one I want) - que is the object.
celui dont je parle (the one I'm talking about) - dont replaces de.

More examples:

De tous ces films, celui que je préfère, c'est le dernier. (Of all these films, the one I prefer is the last.)
Ceux qui arrivent en retard attendront dehors. (Those who arrive late will wait outside.)
La photo dont tu parles, c'est celle qui est sur le mur? (The photo you're talking about, is it the one on the wall?)

The phrase ceux qui ("those who") is worth banking as a fixed opener; it turns up constantly in writing.

The neuter demonstratives: ceci, cela, ca

The four forms above all replace a specific, gendered noun. When there is no noun - when you're pointing at an idea, a situation, or an unnamed thing - French uses the neuter demonstratives ceci, cela and ça.

ceci = this (near, and slightly formal): Écoute bien ceci. (Listen carefully to this.)
cela = that (the default written form): Cela ne me surprend pas. (That doesn't surprise me.)
ça = the spoken contraction of cela: Ça ne me surprend pas. (Same thing, conversational.)

ça is simply cela worn down for speech, and it is everywhere in spoken French: Ça va? (How's it going?), C'est ça. (That's it.), Ça m'énerve. (That annoys me.). In an exam essay or formal letter, write cela; in dialogue or anything informal, ça is natural. They are invariable - no gender, no number, no -ci / -la completion needed, because there is no noun behind them to agree with.

Worked examples

Tu vois les deux voitures? Celle de gauche est à moi. (Do you see the two cars? The one on the left is mine.)
Mon ordinateur est lent; celui de mon père est plus rapide. (My computer is slow; my father's is faster.)
Parmi ces robes, prends celle qui te plaît. (Among these dresses, take the one you like.)
Ceux qui ont fini peuvent sortir. (Those who have finished may leave.)
Quel gâteau? Celui-ci ou celui-la? (Which cake? This one or that one?)
Ce livre n'est pas celui dont je t'ai parlé. (This book isn't the one I told you about.)
Tout ça ne sert à rien. (All of this is pointless.)

Common mistakes English speakers make

Leaving celui to stand alone: je veux celui is wrong - it must be celui-ci, celui de Marc, or celui qui.... Failing to agree the pronoun with the noun it replaces: it's ma voiture et celle de Paul (feminine, matching voiture), not celui de Paul. Reaching for the adjective when you need the pronoun, or the reverse - ce sits before a noun ("ce livre"), celui replaces one ("celui-ci"); they are not interchangeable. Writing ça in a formal essay where cela belongs - they mean the same thing, but ça is the spoken register. And trying to glue -ci / -la onto the neuter forms - cela-ci is not a word; cela and ça are already complete.