You can discover the flat vaults that Viollet Le Duc drew in his Dictionnaire raisonné de l'architecture française du XIe au XVIe siècle (Rational Dictionary of French Architecture from the eleventh to the sixteenth century).

 

It is a cased ceiling upheld by columns resting on ribs starting from the ground up to the keystone. The boxes are decorated with angel musicians and flowers, typically representative of Heaven.