I used to think un(e) could never ever appear after [pronoun] + [être], but then I learnt it’s okay after je, tu, and vous.

tu es un bon ami ✅

Fair enough, but then every sentence must follow one of these rules:

  • [je/te/vous] + [être] + [article] + [noun phrase]
  • [je/te/vous] + [être] + [adjective/title (e.g. nationality, job, etc.)]
  • [il(s)/elle(s)] + [être] + [adjective/title (e.g. nationality, job, etc.)]
  • [c’est/ce sont] + [article] + [noun phrase]
  • [c’est/ce sont] + [adjective/title (e.g. nationality, job, etc.)]

Right? WRONG. French people have since told me that while this is correct:

elle est professeur d’histoire

this is not:

elle est professeur française

because « c’est » works better:

c’est une professeur française

But why?? professeur d’histoire and professeur française are both objective descriptions of the person. One answer I’ve got is that it’s because française is an adjective, so there needs to be a bona fide noun for it to modify. So professeur can no longer appear without un(e) as if it were an adjective. But that’s raised more questions than it’s answered for me:

  1. How is that any different for professeur d’histoire? d’histoire also modifies professeur, yet it’s still allowed to appear without the indefinite article for some reason. Why?
  2. If the presence of an adjective is what necessitates the indefinite article and thus the need to switch from « elle est » to « c’est une », then why does « elle est professeur qui habite à Paris » not work? There’s no adjective in the sentence.

For the latter question, I’ve even been told that it’s because the clause after qui ‘works like an adjective’. But that explanation is so vague and doesn’t tell me what the exact rules are.

One could argue d’histoire also works like an adjective and modifies professeur so that it means « professeur qui enseigne l'histoire ». Yet d’histoire is still somehow okay without un(e). Why? Where do you draw the line? What exactly are the rules? If the rule is ‘if it’s like an adjective…’ then when does something become similar enough to an adjective to qualify for this? I’ve been stuck on this question for a whole week and I’m so frustrated. No more comparisons please. What are the rules? What exactly are the exact rules?

Also could I please see nontrivial examples of [il(s)/elle(s)] + [être] + [title]? I wanna see how long/descriptive they can get before they must take on the indefinite article.

  • 2
    professeur d’histoire and professeur française both might be "objective descriptions" as you say (?) but grammatically they're totally different. d'histoire in professeur d'histoire is not an adjective, it is a noun supplement. In professeur française, française is an adjective. You can say elle est française, c'est une femme française : the adjective can be placed in different places in the sentence (whether it is attributive or predicative). In a noun supplement you can't move the elements.
    – None
    Commented Dec 31, 2023 at 17:41
  • 2
    I suggest you study carefully the use of c'est. There are plenty of websites that deal with this French structure (of course some seem better than others). But don't expect "exact rules". We have to work with rules, exceptions and usage.
    – None
    Commented Dec 31, 2023 at 18:53
  • 2
    Nowadays, it is usually written as: professeure française.
    – jlliagre
    Commented Dec 31, 2023 at 22:35

2 Answers 2


Don't expect to find hard and fast rules about that type of case, but more as a rule of thumb:

[il(s)/elle(s)] + [être] + [adjective/title (eg nationality, job, etc)]

in that construction, you cannot modify the subject (il/elle) with another qualifier. Any modifiers you apply will pertain to the attribut du sujet, i.e. the predicative adjective/title. They can be as long as needed.

Il est professeur émérite d'histoire de l'art à mi-temps à la Sorbonne à Paris

(None of the modifiers apply to il. He is not in Paris right now, he teaches in Paris. He is not émérite, it's part of his title. etc.)

Elle est anglaise sur le papier à Londres mais thaïlandaise de cœur

Following the same logic,

elle est professeur française

doesn't work because you're really trying to qualify the subject elle, not the predicate professeur. The predicate adjective and noun conflict, one of them must go away.

C'est une professeur française

in contrast, is correct because française qualifies the predicate professeur, not the subject c'(e) which is a neutral construct.


The solution is in the word UNE, in the answer of the @guillame31 he show the confusion between noun and adjective. But when you add in the second form the word UNE > elle est une professeur française became correct.

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