Why does un become de in a negative sentence?

Because un, une, des, du, and de la all state a quantity, and negating the sentence removes it. French marks that empty quantity with de: j'ai une sœur becomes je n'ai pas de sœur. The article is not deleted, it is swapped for the zero form.

Does this happen after every negative word?

After every genuine negation, yes: pas, plus, jamais, guère, and ni all produce it. Il n'y a plus de pain, elle ne prend jamais de dessert. The only negative-looking structure that does not is ne… que, which means only.

Why is it ce n'est pas un problème and not pas de problème?

Because after être the noun states what something is rather than how much of it there is. With no quantity to cancel, the article stays: ce ne sont pas des amis, ce n'est pas une erreur.

What about je n'aime pas le chocolat?

Le chocolat is a definite article naming a whole category, so nothing changes. Learners often overcorrect this to je n'aime pas de chocolat, which is wrong. Only un, une, des, du, de la, and de l' are affected.

Does de become d' before a vowel?

Always: pas d'argent, pas d'idée, pas d'eau, pas d'hôtel. The elision is compulsory in writing and in speech, and pas de argent is never possible.

French grammar · Beginner

Negative De in French: Why Un and Du Become De After a Negation

Written by Camille Laurent, Lead French Curriculum Editor · Reviewed May 2026

When a French sentence turns negative, the indefinite and partitive articles un, une, des, du, de la collapse into a single de. J'ai un chien becomes je n'ai pas de chien, and je bois du café becomes je ne bois pas de café. Definite articles, possessives, and the verb être are the exceptions that keep their article.

Je n'ai pas de voiture.

I don't have a car.

What it is

Un, une, des, du, and de la all express a quantity: one of something, or some of something. A negation wipes that quantity out, and French marks the resulting emptiness with a bare de. So the article does not disappear, it is replaced by the one form that says none at all.

J'ai du temps. → Je n'ai pas de temps. — I have some time. → I don't have any time.

How to spot it

Look at the article in the affirmative sentence. If it is un, une, des, du, de la, or de l', it becomes de in the negative. Anything else stays as it is.

Il n'y a pas de train le dimanche. — There's no train on Sundays.
Nous n'avons pas d'enfants. — We don't have children.
Elle ne boit jamais de vin. — She never drinks wine.
Je n'aime pas le vin. — I don't like wine. (definite article, unchanged)

De elides to d' before a vowel or a mute h: pas d'argent, pas d'idée, pas d'hôtel.

Negative De Quick Reference

What happens to each article under negation

Affirmative	Negative	What changed
J'ai un chien.	Je n'ai pas de chien.	un → de
Elle a une idée.	Elle n'a pas d'idée.	une → d'
Nous avons des amis ici.	Nous n'avons pas d'amis ici.	des → d'
Je bois du café.	Je ne bois pas de café.	du → de
Il mange de la viande.	Il ne mange pas de viande.	de la → de
J'aime le café.	Je n'aime pas le café.	nothing: definite article
C'est un problème.	Ce n'est pas un problème.	nothing: the verb is être
J'ai ton stylo.	Je n'ai pas ton stylo.	nothing: possessive

Common Negative De Examples in French

The rule at work with each kind of object:

Countable Things

Je n'ai pas de frère.: I don't have a brother.
Il n'a pas de vélo.: He hasn't got a bike.
Elle n'a pas d'ordinateur.: She doesn't have a computer.
Nous n'avons pas de questions.: We don't have any questions.

Whether the noun is singular or plural, the article is the same bare de. Only the noun changes.

Food, Drink, and Uncountables

Il ne reste pas de pain.: There's no bread left.
Je ne prends pas de sucre.: I don't take sugar.
On n'a pas d'eau chaude.: We don't have any hot water.
Elle ne met pas de beurre dessus.: She doesn't put butter on it.

This is where the change is most visible, because du and de la are so frequent in the affirmative.

After Other Negative Words

Il n'y a plus de lait.: There's no more milk.
Je n'ai jamais eu de problème avec eux.: I've never had a problem with them.
Nous n'avons guère de temps.: We have hardly any time.
Elle n'a ni frère ni sœur.: She has neither a brother nor a sister.

Any negative word does this, not just pas: plus, jamais, guère, and ni all trigger the same collapse.

Set Phrases Built on Pas De

Pas de problème !: No problem!
Pas de souci.: No worries.
Il n'y a pas de quoi.: Don't mention it.
Pas de chance aujourd'hui.: No luck today.

These fragments have no verb at all, and they still follow the rule: it is always pas de, never pas du.

How Negative De Works

One idea explains the rule, and three boundary conditions explain every exception to it.

De Is the Zero-Quantity Article

Un means one, du and des mean some. Negating the sentence removes the quantity entirely, and French needs something in the article slot to say so. De is that something, which is why it appears in place of all five forms.

J'achète des tomates ; je n'achète pas de tomates.

I'm buying tomatoes; I'm not buying any tomatoes.

Some → none, so du and des → de.

Definite Articles Are Untouched

Le, la, les point at something specific or at a category as a whole, not at an amount, so a negation has nothing to cancel. Je n'aime pas le café is about coffee in general and keeps le.

Elle ne supporte pas la chaleur.

She can't stand the heat.

No quantity, no change.

Être Keeps Its Article

After être, the noun is not something being had or consumed, it is an identity. There is no quantity in play, so un, une, and des survive: ce n'est pas un accident, ce ne sont pas des touristes.

Ce n'est pas une bonne idée.

That isn't a good idea.

être → the article stays.

Possessives and Demonstratives Stay Too

Mon, ton, son, ce, cette are determiners of identification rather than quantity, and they behave like the definite article. Je n'ai pas ton parapluie, not pas de ton parapluie.

Je ne veux pas ce modèle.

I don't want this model.

Only un, une, des, du, de la change.

Common Mistakes with Negative De

Incorrect: Je n'ai pas un chien. — I don't have a dog.

Correct: Je n'ai pas de chien. — I don't have a dog.

English keeps a in the negative, so learners keep un. French replaces it with de, because the negation has cancelled the quantity that un expressed.

Incorrect: Il n'y a pas des places. — There aren't any seats.

Correct: Il n'y a pas de places. — There aren't any seats.

Des is the plural of the quantity article, so it collapses to de just like du and un. Pas des only survives in a contrastive sentence.

Incorrect: Je n'aime pas de fromage. — I don't like cheese.

Correct: Je n'aime pas le fromage. — I don't like cheese.

This is the rule applied too widely. Aimer takes the definite article to talk about a category, and a definite article never changes under negation.

Incorrect: Ce n'est pas de problème. — That isn't a problem.

Correct: Ce n'est pas un problème. — That isn't a problem.

After être the article survives, because the noun identifies rather than counts. The verbless exclamation Pas de problème ! is a separate fixed phrase.

Three Cases Where the Article Comes Back

Each of these looks like a negation but is not doing the job that negative de responds to.

Ne… que is a restriction, not a negation

Ne… que means only. It limits the quantity rather than cancelling it, so the article stays exactly as it was in the affirmative.

Je ne bois que du thé.: I only drink tea.
Il n'y a qu'une place libre.: There's only one seat free.
Elle ne mange que des légumes.: She only eats vegetables.

Compare je ne bois pas de thé, I don't drink tea, with je ne bois que du thé, I drink nothing but tea.

Contrastive negation

When the negation targets one specific thing in order to correct it, rather than denying any quantity at all, the original article is kept.

Je n'ai pas acheté des pommes, mais des poires.: I didn't buy apples, I bought pears.
Ce n'est pas du beurre, c'est de la margarine.: That isn't butter, it's margarine.
Il ne veut pas du café froid, il en veut du chaud.: He doesn't want the cold coffee, he wants hot coffee.

The test is whether a mais clause is coming. If you are replacing one item with another, keep the article.

Adjectives in front of the noun

When an adjective precedes the noun, de still appears, but be careful with fixed plural pairs, which behave like single nouns and keep des.

Il n'y a pas de bons restaurants dans ce quartier.: There aren't any good restaurants in this area.
Je n'ai pas de vieux amis ici.: I don't have any old friends here.
Ce ne sont pas des petits pois, ce sont des haricots.: Those aren't peas, they're beans.

Des petits pois is one lexical item, peas, so it resists the change in the same way a compound noun would.

Negative De FAQs

Why does un become de in a negative sentence?: Because un, une, des, du, and de la all state a quantity, and negating the sentence removes it. French marks that empty quantity with de: j'ai une sœur becomes je n'ai pas de sœur. The article is not deleted, it is swapped for the zero form.
Does this happen after every negative word?: After every genuine negation, yes: pas, plus, jamais, guère, and ni all produce it. Il n'y a plus de pain, elle ne prend jamais de dessert. The only negative-looking structure that does not is ne… que, which means only.
Why is it ce n'est pas un problème and not pas de problème?: Because after être the noun states what something is rather than how much of it there is. With no quantity to cancel, the article stays: ce ne sont pas des amis, ce n'est pas une erreur.
What about je n'aime pas le chocolat?: Le chocolat is a definite article naming a whole category, so nothing changes. Learners often overcorrect this to je n'aime pas de chocolat, which is wrong. Only un, une, des, du, de la, and de l' are affected.
Does de become d' before a vowel?: Always: pas d'argent, pas d'idée, pas d'eau, pas d'hôtel. The elision is compulsory in writing and in speech, and pas de argent is never possible.