The Church of San Luis de los Franceses is an outstanding example of 18th century Baroque architecture. It was designed by the architect Leonardo de Figueroa and built between 1699 and 1730 on behalf of the Society of Jesus. After the expulsion of the Jesuits from Spain in 1835, it was put to different uses and was finally deconsecrated.

With regard to its exterior, it is oriented according to the path of the sun or analemma, in such a way that the main altar to the west receives abundant light, especially in spring. The main door faces east, where the sun rises. The altar of San Estanislao, to the north, and the altar of San Francisco Borja, to the south, receive light on the feast day of each saint.

On the other hand, inside the church, it should be noted that the floor plan is in the shape of a Greek cross. Above it is a dome, 16 Solomonic columns that appear to support the weight of the dome, which in reality is supported by four pillars that are hollowed out to house chapels inside. The four pillars are concealed by the four smaller altarpieces, which are then covered by four balconies and four lattices. Only the two Solomonic half columns of the main altar are original, the rest belong to the last restoration. The stone columns are stuccoed so that they could be painted, although they were never painted.

Higher up, in the second section, there is a tribune with eight semicircular arches and a set of balconies enclosed by lattices on the pillars that support the dome. The dome is raised on a circular drum and has large windows that give it great luminosity. If the different points of the dome are connected by lines, an octagon or an eight-pointed star or Solomon's star, which can be seen in many places in the temple, emerges. At the bottom of the dome is a representation of religion with the word Religio. This figure, apparently female, holds the Cross with her right hand, symbol of Christ and also symbol of his death, vindicating Christ as Martyr, and with her left hand she holds a palm in allusion to the resurrection. Behind this figure is the Ark of the Covenant.

Most of the altarpieces, both sculptural and architectural, are the work of Duque Cornejo, while most of the paintings are by Domingo Martínez, who painted them between 1743 and 1750.

The main altarpiece is presided over by a canvas of Saint Louis, King Louis IX of France, and the six side altarpieces are dedicated to different Jesuit saints.

The crypt is located underneath the church and forms the foundations of the church. It allows us to observe the systematic approach Leonardo de Figueroa used in the construction process, using four hollowed-out pillars and distributing the weight in arches. During the restoration work, the skeletal remains of numerous corpses have been recovered, most of them women, possibly nuns, but also children and men.