An essential cog in the surveillance of maritime approaches

Spread along the coastline, the Méditerranée semaphore chain, an operational component of the Marine nationale, is manned by 19 semaphores (12 on the mainland and 7 in Corse), with a crew of around ten sailors taking turns 24 hours a day to watch over their assigned area using various sensors (optical, radar, radio, drone, etc.)

Placed under the operational control of the commander of the Méditerranée maritime zone and integrated into the maritime defense of the territory (DMT) system, they ensure the surveillance of French maritime approaches along nearly 2,000 km of coastline. They contribute to the State Action at Sea (AEM) under the authority of the maritime prefect of the Méditerranée, by participating in missions to monitor navigation, preserve the marine environment, detect illegal activities at sea, and safeguard human life.

The final bulwark of the national territory against threats that may come from the sea and in connection with the vessels and aircraft of the Marine nationale, they are there to detect, query, identify and track civil and military vessels entering waters under French sovereignty and jurisdiction. In 2025, 257,416 civil vessels (+ 3%) and more than 500 foreign military vessels (- 22%) were tracked.

NUMEROUS EXERCISES Furthermore, they participated in numerous large-scale exercises and operations on the Méditerranée coast.

Thus, the semaphores of Saint-Jean-Cap-Ferrat and la Garoupe (Antibes) played a major role in securing the 3rd United Nations Ocean Conference (UNOC 3) in June 2025 in Nice. For 10 days, they monitored maritime traffic and controlled the restricted nautical and airspace zones in the baie des Anges and the rade de Villefranche-sur-Mer. Reinforced by personnel from other semaphores, they provided early warning detection to the mobilized nautical units while participating in their coordination on the water.

Regarding AEM, the role of the semaphore chain is fundamental, through its territorial network and sensors, to ensure compliance with various regulations and to support the regional operational monitoring and rescue center of the Méditerranée (CROSS MED) as part of its missions for sea rescue and monitoring of navigation and pollution.

• 3 169 navires de commerce surveillés dans les Bouches de Bonifacio (- 2%) ; • 1 485 suspicions d'infractions à la réglementation reportées (+ 16%) ; • 1 157 concernant le mouillage (+ 18%) dont 738 liées à la posidonie (+ 4%) ; • 134 concernant la pêche (- 30%) ; • 167 concernant la sécurité maritime (+ 46%) ; • 1 091 soutiens aux opérations d'assistance et de sauvetage en mer (+ 35%) ; • 10 945 avis urgents aux navigateurs et bulletins météorologiques diffusés à la VHF (+ 14%).