Indefinite articles are used to present a being or a thing without identifying it precisely. They also signal membership in a category, as when a noun is presented as a member of a larger group. In everyday use, they are placed before the noun and agree with it in gender and number.

The indefinite article takes the form un with a masculine singular noun, une with a feminine singular noun, and des with a plural noun. This form does not depend on the adjective that accompanies the noun, because the article remains placed before the noun group. The choice of the form indicates only the gender and number of the noun it introduces.

IdéeIdea	ExempleExample
Un introduit un nom masculin singulier.A introduces a masculine singular noun.	un styloa pen
Une introduit un nom féminin singulier.A feminine singular noun introduces.	une fleura flower
Des introduit un nom pluriel.Des introduces a plural noun.	des pommesapples

An indefinite article presents an unidentified referent, that is, a new element in the discourse. It can introduce an object, a person or a group without specifying which. This value contrasts with the precise identification of definite articles, to be reviewed with Definite Articles.

IdéeIdea	ExempleExample
L’article indéfini présente un élément non identifié.The indefinite article presents an unidentified element.	J’ai acheté un vélo.I bought a bicycle.
L’article indéfini peut introduire un membre d’une catégorie.The indefinite article can introduce a member of a category.	C’est une artiste.She is an artist.
Des marque un pluriel indéfini.Des marks an indefinite plural.	J’ai vu des fruits.I saw some fruits.

After negation markers such as pas, plus, and the other negation markers, the indefinite article becomes de or d' before a vowel. The use of ne then does not function as a quantifying article, but as a marker for the disappearance of the indefinite in the negative sentence. This opposition is distinguished from the partitive value, to be compared with [Partitive Article].

IdéeIdea	ExempleExample
La négation remplace l’article indéfini par de.Negation replaces the indefinite article with de.	Je n’ai pas de pain.I don’t have any bread.
La négation remplace l’article indéfini par d’ devant voyelle.Negation replaces the indefinite article with de before a vowel.	Je n’ai pas d’amis.I don’t have any friends.
Des devient de dans la négation.Des becomes de in negation.	Elle n’a plus de livres.She no longer has any books.

Quantity expressions such as beaucoup de or peu de retain de after them. This structure is regular and does not take the plural form of indefinite articles. It also differs from the absence of an article, which is treated separately in [Absence d'article].

IdéeIdea	ExempleExample
Beaucoup de exige de.Beaucoup de requires de.	Beaucoup de personnes arrivent.Many people arrive.
Peu de exige de.Beaucoup de exige de.	Peu de temps reste.Little time remains.
Une expression de quantité précède le nom sans article indéfini.A quantity expression precedes the noun without an indefinite article.	J’ai pris assez de thé.I have had enough tea.

The indefinite article agrees in gender and number with the noun, and it always appears before it, even when an adjective follows or precedes it. After être (to be), the indefinite article is often omitted in characterization clauses, while it remains present with c'est to identify someone or something. In spoken language, omission can also be more frequent, and certain regional varieties, notably in Quebec, show slightly different uses of the indefinite article and the partitive.

IdéeIdea	ExempleExample
L’article s’accorde avec le nom.The article agrees with the noun.	une idée clairea clear idea
L’article précède toujours le nom.The indefinite article always precedes the noun.	un vieux livrean old book
Après être, l’article peut être omis.After être, the article may be omitted.	Il est médecin.He is a doctor.
Avec c’est, l’article reste fréquent.With c'est, the article remains frequent.	C’est un médecin.He is a doctor.

Un, une and des present a noun without identifying it precisely and agree with its gender and number. In negation, they become de or d', and after expressions of quantity, de is also imposed. To distinguish correctly the indefinite, the partitive and the absence of an article, one must observe both the sentence structure and the function of the noun within the noun phrase.