A man has been arrested after barricading himself inside a museum in the town of Saint Raphael while reportedly shouting threats.
Emergency services scrambled to the Archaeological Museum of Saint Raphael in Var, in the south of the country.
French media said it was unclear if the man was armed or if there were hostages but said he had written Arabic on the walls.
According to AFP, one of the messages states that "the museum will become a hell".
In an update at 10.30am, police said that a man had been arrested.
A police spokesman said: "We must remain very cautious because we do not have at the moment any information on his motivation, we would be more faced with an imbalance."
Police did not give any further details about the arrest on their Twitter page.
The force urged people to avoid the area during the incident.
Pictures and video from the scene show police descending on the museum on Thursday morning.
