The Saint-Genest church is located on a square which extends rue Lamartine, along the Quai Alsace Lorraine. Rebuilt from 1625, its sobriety reflects the classic taste of the beginning of the Counter-Reformation observed in Rome a hundred years earlier.
The facade is arranged on two levels with superimposed orders, separated by a cornice, with a frieze with triglyphs and metopes. A rounded pediment crowns the whole.
In the central niche is installed (since 1869), the statue of Gérard Tenque, founder of the Hospitallers of St-Jean-de-Jérusalem and born in Martigues in 1040. The statue was sculpted in the years 1880-1890 by a mason from Martigues, Nazaire Bernard.
The west facade was renovated in 2019.
The interior of the church is characterized by its clarity, the quality of its stone and the plastic work. This gives it a monumental appearance. The bell tower at the back faces the Annonciade chapel. It was built in 1859/60 by Numa Regulus Dornier, city architect, who also designed the bell tower of the Ferrières church.
On the south wall side, a wooden door from the previous building has been kept. It was once the main entrance to the building.