Designed in the French Classical style by Jules Hardouin-Mansart, this church was built between 1677 et 1706. Two cupolas fit one inside the other, illuminated by “hidden light”. The beauty of the domes contrasts with the robust aspect of the square base, based on the design of a Greek cross. The dome, originally sky blue and gilded, is striking for its dignity and majesty. The circular “crypt” houses the tomb of Napoleon, a red porphyry sarcophagus.