Ratonneau is one of the islands of Friuli archipelago in the Mediterranean Sea , off the southern coast of France near Marseille . It is relatively long and thin, approximately 2.5 km long but at most 500 m wide and generally much narrower. It was connected to the near island of Pomègues , which runs roughly parallel, by a mole constructed in 1822 to create a port area.
The Ancient Roman fleet that besieged Marseilles in 49BC was moored by the island. Later, the island was used to quarantine foreign sailors, particularly those with cases of cholera and Leprosy. The neoclassical hospital was built in the late 1880s to a design by Michel-Robert Penchaud , but was destroyed in the Second World War .
The center of the island is occupied by a strong, with a smaller fort at its western tip. The smaller island of If lies to the south east.
The island has several beaches. Today, the island is partially visited by tourists, by ferries that connect the island to the Old Port of Marseilles in the summer season. The island includes some tourist restaurants, some tourist shops, a fire station, and a town hall. Motor vehicles are banned.