J.K. Rowling studied French during part of her time in Paris.
She attended the University of Exeter and completed a degree in French and Classics. As part of that course, she spent a year in Paris as an assistant teacher. The experience gave her direct contact with French language and culture before she began her professional writing career.
Rowling’s French background is also reflected in the Harry Potter books through French characters and institutions, including Fleur Delacour and Beauxbatons Academy of Magic. Those fictional details should not be mistaken for a claim that the entire series was based in France; Hogwarts and most of the central story are located in Britain.
Her university studies are sometimes oversimplified as a degree in English literature, but that was not her subject. French and Classics provided the formal academic foundation recorded in biographies, while her later work history and reading supplied additional influences on her writing.