The newspaper said the plaintiff, whom it did not name, filed the lawsuit in early October at the Paris judicial court.

It said the plaintiff was also suing EDF for harassment, without detailing those allegations.

EDF declined to comment on the allegations, but said safety at its nuclear sites was its priority. "Transparency and compliance with regulations are strictly applied and respected at all sites", it said.

A spokesperson for the Paris judicial court was not immediately available for comment.

A spokesperson for France's ASN nuclear regulator referred to a comment made to Le Monde, in which the watchdog said it hadn't found any incidents of a cover-up at the Tricastin plant.

(Reporting by Benjamin Mallet and Matthieu Protard; Editing by Mark Potter)