Adjectifs Possessifs et Démonstratifs

The two small word-families on this page are technically determiners in modern grammar, but most reference works — and most language teachers — still treat them as adjectives, because they sit in the noun phrase and agree with the noun the way ordinary adjectives do. In French these two families are les adjectifs possessifs (my, your, his/her) and les adjectifs démonstratifs (this, that, these, those). Together they account for an enormous slice of everyday speech: mon père, cette maison, ses enfants, ce livre-là. They look harmless, and a beginner can almost always guess what they mean. But each family hides one specific trap that English speakers fall into again and again — and once you see the trap, the system becomes simple.

This page covers both families side by side, explains the agreement logic that unites them, drills the special pre-vowel forms (mon amie, cet ami) that override the obvious feminine choice, and ends with the most common mistakes.

What unites the two families

Possessives and demonstratives share a single rule: they agree with the noun they introduce, not with anything else in the sentence. The agreement is in gender (masculine or feminine) and number (singular or plural). They sit in the determiner slot, so they replace the article — you say mon livre, not le mon livre; cette maison, not la cette maison.

In each case the form of the determiner — mon, cette, ses — is fixed by the noun that follows. Mon because livre is masculine; cette because maison is feminine; ses because enfants is plural. The possessor or the speaker's pointing-finger does not shape the form. The noun does.

This is the single most important point on the page, and it is where English speakers are tripped up most often, because English does the opposite for possessives: his book and her book differ because his and her mark the possessor, not the book. We will return to this directly.

Possessive adjectives: the full inventory

There are six possessors in French — I, you (familiar), he/she/it, we, you (formal or plural), they — and each possessor has up to three forms depending on whether the possessed noun is masculine singular, feminine singular, or plural.

Notice the pattern: mon / ton / son (the singular possessors) split into masculine and feminine forms. Notre / votre / leur (the plural possessors) do not — they have one singular form for both genders, and a plural form ending in -s. This asymmetry has nothing to do with the speaker; it is a quirk of how Latin's possessives evolved.

The fixed point: choose the form that matches the noun. Frère is masculine, so mon. Sœur is feminine, so ma. Parents is plural, so mes. The same logic for every line of the table.

The trap of son livre

In English, his book and her book differ because his and her mark the possessor. In French, the possessor's gender is invisible. Son livre tells you only that the possessed noun (livre) is masculine. The book might be his, or it might be hers — French does not distinguish.

Both sentences use exactly the same word — son — even though the possessor's gender is opposite. Context tells you who owns the book; the determiner does not. This is the single most counter-intuitive point in French possessives for English speakers, and it produces a steady stream of errors in which learners pick sa because the possessor is female.

A useful drill: imagine a brother and sister, Pierre and Marie. Both have a father (père, masculine) and a mother (mère, feminine). All four phrases below mean different things in English but use only two forms in French.

• son père = his father (Marie's brother) and her father (Pierre's sister)
• sa mère = his mother and her mother

The French determiner is doing work English does not even attempt: marking the possessed-noun's gender. The work English does — marking the possessor's sex — French never does in the determiner.

The pre-vowel rule: mon amie, ton école

Here is the second trap. The feminine forms ma, ta, sa end in a vowel sound (-a). When the noun that follows starts with a vowel sound, you would have two vowels colliding: ma amie, ta école, sa idée. French dislikes this hiatus and resolves it by switching to the masculine-singular form, which ends in a consonant sound: mon, ton, son.

The noun is still feminine — amie, école, idée are all feminine — and any adjective that goes with them will still take feminine agreement. Only the determiner shifts.

Note ancienne — feminine, because amie is feminine. The pre-vowel switch on the determiner does not propagate to the adjective.

The trigger is the vowel sound of the noun, not the spelling. Words starting with a silent h (h muet) take mon / ton / son the same way: mon habitude, ton heure, son histoire. Words starting with an aspirated h (h aspiré) keep ma / ta / sa: ma haine, ta hauteur. The aspirated h category is small and idiosyncratic — covered in detail on its own page.

Demonstrative adjectives: the full inventory

Demonstratives point. They translate roughly to this, that, these, those, but French simplifies the system: there is only one demonstrative for each gender-and-number combination. Where English splits this book / that book, French uses ce livre for both — context, or an optional suffix, makes the distance explicit.

Four written forms total: ce, cet, cette, ces. Three pronunciations, because cet and cette sound identical (/sɛt/).

The plural ces is invariable — it is used for both masculine and feminine plural nouns. Ces livres (m.), ces tables (f.), ces enfants (m. or mixed): all ces.

Cet: the same logic as mon before vowels

The masculine form ce ends in a sound (/sə/) that collides awkwardly with a vowel-initial noun. So before a masculine noun starting with a vowel sound, ce becomes cet — pronounced like cette (/sɛt/) but spelled with one t.

The trigger is the same as for mon / ton / son: a vowel sound, including silent h (cet hôtel, cet homme, cet histoire-là... wait — histoire is feminine, so cette histoire; hôtel and homme are masculine, so cet hôtel, cet homme). The form cet exists only for masculine singular before vowels. There is no parallel before-vowel form for cette (it already ends in a consonant) or ces (the -s liaison handles the sound, and you simply hear /sez/ before a vowel).

Adding -ci and -là to mark distance

Because ce / cet / cette / ces alone do not distinguish this from that, French uses two suffixes attached to the noun with a hyphen: -ci for the closer item and -là for the farther one. The grave accent on là is not optional — la without the accent is the feminine article (the), a different word.

In everyday French, the -ci / -là distinction is mostly used when you are explicitly contrasting two items. If you just want to say this dog without contrast, ce chien is enough — and là gets used as a default, slightly tilting toward "that," but really meaning "the one I'm pointing at."

The -là in everyday speech often does not really mean far away; it means the one I have in mind. This is one of the small register details that mark a fluent speaker.

Comparing the two families side by side

The two families share more than they look like they do. Both:

• Sit in the determiner slot (replacing the article)
• Agree with the noun in gender and number
• Have a special form before vowel-initial masculine words (mon → mon in fem., cet for masc.)
• Become invariable in the plural (mes / nos / vos / leurs across genders; ces across genders)

The differences are also small but real. Possessives mark ownership or relationship; demonstratives mark identification by pointing. You can layer one of each onto a noun phrase only if you replace one with another structure — for example, with the demonstrative pronoun celui: celui de mon frère (the one of my brother = my brother's).

A noun phrase takes one and only one determiner. Ce mon livre is ungrammatical; you choose either the demonstrative or the possessive.

Register notes

Both families are (neutral) in register and appropriate in any context — formal letter, casual conversation, academic writing, song lyric. The contraction cet before a vowel and the suffixes -ci / -là are likewise neutral. The only register-marked variant is the (formal/literary) alternative cette + noun + -ci used for emphasis in older or rhetorical writing — en cette époque-ci, en ce temps-là — which lands somewhere between elevated prose and historical narration. The everyday spoken language uses these forms freely without special tone.

Common mistakes

The first two errors come from English transfer: making the determiner agree with the possessor. Train the reflex by always asking what is the gender of the noun? before you pick son or sa. The third and fourth are the pre-vowel rule, which is invisible until you hear it; the fifth is gender-and-number confusion typical of early A1; the sixth is a spelling slip that changes the word entirely (without the accent, la is the article the).

Key takeaways

• Possessives and demonstratives both sit in the determiner slot and agree with the noun, never with the possessor or the speaker.
• The six possessors give six rows; the singular possessors (mon / ton / son) split into m./f./pl., the plural possessors (notre / votre / leur) only split sg./pl.
• Son / sa / ses mean his OR her — context decides; the determiner never tells you the possessor's sex.
• Before a vowel sound, feminine ma / ta / sa become mon / ton / son; masculine ce becomes cet. The noun's gender does not change.
• Demonstratives ce / cet / cette / ces cover both this and that; add -ci or -là to make the distance explicit.
• Master these two families early. Together they cover the determiner slot in roughly half of all noun phrases in spoken French.