The Church of St. Louis of the French is a Roman Catholic church in Rome, not far from Piazza Navona. The church is dedicated to the Virgin Mary, to St. Denis the Areopagite and St. Louis IX, king of France. The church was designed by Giacomo della Porta and built by Domenico Fontana between 1518 and 1589, and completed through the personal intervention of Catherine de' Medici, who donated to it some property in the area. It is the national church in Rome of France. It is a titular church.