Authorities said the hold-up took place in broad daylight at the Carlton Hotel on the promenade in Cannes, famous for its annual film festival that attracts a glittering array of celebrities.
Hotel management contacted by AFP declined to comment.
During the film festival in May, thieves stole jewellery worth USD 1.4 million that was due to be loaned to movie stars from a local hotel in a pre-dawn heist.
A strongbox containing jewels was ripped out of the wardrobe and carried off, they said.
