The Cassidaigne, Maritime navigation beacon in Cassis, France.

The Cassidaigne is a stone tower built in 1859 on the Cassidaigne shoal, 7.5 kilometres off Cassis and beyond Cap Canaille. It rises 23 metres straight from the water as a plain pale shaft without windows or railings, tapering slightly to a blunt top. A navigation mark for an isolated danger sits on the summit.

The stone tower was built in 1859 on the Cassidaigne shoal, a shallow rise 7.5 kilometres off Cassis near Cap Canaille, and takes its name from the Cassidaigne pit. It was repaired during the second quarter of the 20th century. It stands 23 metres tall and is topped by an isolated danger mark.

The name comes from the Cassidaigne pit, the deep underwater depression beside the shoal the tower marks. The tower carries an isolated danger mark on top, a navigational signal rather than a lighthouse lantern, and its light shows two white flashes every six seconds, visible for seven miles.

The tower stands on the Cassidaigne shoal 7.5 km off Cassis, beyond Cap Canaille, so it is seen only from a boat. Its white light shows two flashes every six seconds and reaches seven nautical miles, making it easiest to pick out after dark or in low visibility.

The tower carries an isolated danger mark at its top, a navigational signal reserved for a single hazard surrounded by clear water. Its light shows two white flashes every six seconds and reaches seven nautical miles. The structure was repaired in the second quarter of the 20th century.