Fort de Bouc, A fort in Martigues, in the Bouches-du-Rhône department.

Fort de Bouc is a stone fortification on the islet of Bouc at the entrance to the Canal de Caronte. Its square tower was built in the 13th century, not the 15th, and was later enclosed by a bastioned wall. A five-arched bridge links two thick walls; the right wall is topped by two small domed watchturrets and three flagpoles, and the stone is marked with pockmarks.

A square tower was built in the 13th century to guard the entrance to the Canal de Caronte. In 1536 it withstood an attack by Andrea Doria's fleet. From 1605 to 1610, engineers Raymond and Jean de Bonnefons built a bastioned enclosure around it. The fort was decommissioned in 1889, leaving only the lighthouse keeper in residence.

The fort's other name, Fort Vauban, recalls the 17th-century military engineer whose plans shaped its present form. In the 20th century the site served as an artillery training centre during World War I, and from 1942–1943 German forces used it as a coastal artillery position, leaving large quantities of ammunition behind.

The fort stands on the islet of Bouc facing the Port de Bouc, at the mouth of the Canal de Caronte; today it marks the entrance to the industrial port of Martigues-Lavéra. The commune of Martigues bought it in 1993, cleared it of mines and restored it. The stone surfaces are pocked by shell and bullet marks, and the ground is uneven, so wear sturdy shoes.

During World War II, the Germans occupied the fort and the Allies later damaged parts of it to prevent further military use, leaving visible scars that tell of this conflict. The Bonnefons family, a line of French engineers, directed the major reinforcement work in the early 1600s and shaped much of the fort's current appearance.