A passenger ferry docked in the southern French port of Marseille was evacuated on Sunday after an explosion was felt on board, with authorities investigating if it was caused by an old wartime bomb.

France has been on high alert following the Bastille Day truck attack in Nice which killed 84 and the jihadist murder of a priest last week.

All the passengers had already disembarked after their voyage from Corsica and the blast did not cause any damage to the ship or dock, officials said.