The Neo-Classical chapel was built in 1816 by the widow of Philippe Égalité and later extended by Louis-Philippe, who altered its exterior, adding pinnacles and "Gothic" spires. It is a tribute to the 19C by the quality of its architecture and contributions by talented artists, responsible for the recumbent figures and stained glass, in particular. Notice the five painted mirrors by the Sèvres factory and in the main crypt, the mausoleum of the royal family.