A Michelin star chef has quit his job at a luxury hotel in Biarritz after a kitchen hand was reportedly tied up naked for hours during an initiation.

Chef Aurélien Largeau ran the five-star restaurant at the Hôtel du Palais in south-western France until 21 December, the hotel management said.

A preliminary investigation into charges of sexual assault and violence was opened on Thursday, AFP reported.

It is understood no formal complaint has been made.

Hyatt, the hotel management company, said appropriate action had now been taken, but did not specify what that was.

According to regional French newspaper Sud Ouest, a young kitchen aide was allegedly tied to a chair naked for hours while surrounded by others during the incident in early December.

It was reported that footage of the alleged incident was shared on social media. The footage has since been removed.

Mr Largeau told French media that reports of the incident were defamatory and described them as a "monstrous attack" on his honour. The BBC has approached Mr Largeau for comment.

In a statement sent to the BBC, Hyatt - which runs but does not own the hotel - said an investigation was launched "immediately" by the hotel management team following "concerning allegations and imagery regarding an incident in the premises of the hotel".

"The incident did not reflect the strong values we all stand for, and the appropriate decisions have now been taken."

It said "the security, wellness and well-being of our colleagues, guests and partners are always our utmost priorities".

La Table d'Aurélien Largeau is situated on Biarritz's famous Atlantic beach. The restaurant offers diners "a unique experience" in which they can "savour sophisticated and contemporary French cuisine". (BBC)