My native language is Romanian, one with a lot of French neologisms that resulted in many (more or less) false friends. Thus, I was very surprised in France to hear people saying about a girl with light skin and brown hair that she was "une jolie brune". — The French brunet has given an identical term in Romanian and brunette has given the word brunetă, both much more actively used than in French, and meaning people with somewhat darker skin and hair, and usually dark-colored eyes, something like the "Mediterranean" type, let's say George Clooney and Claudia Cardinale

but not simply people with brown, dark-brawn or black hair: not just "not blonde" (which to me seems to be the real meaning of brune in expressions like "jolie brune" ou "plutôt brune").

(I think this broader meaning is exceptional for a neologism, which normally gets a more limited and more specific meaning compared to the original.)

CNTRL says about brun, brune:

Celui, celle dont les cheveux sont bruns

and about brun, brunette:

A.− Emploi adj.
1. Rare. Légèrement brun(e), tirant sur le brun. ...
2. P. méton. [En parlant de pers.] Dont les cheveux tirent sur le brun...

B.− Emploi subst.
1. Jeune femme, jeune fille dont les cheveux sont bruns, tirent sur le brun. 

And is there a term for people with fair skin and black/dark hair?