Metz Cathedral through the centuries

To coincide with the 800th anniversary of Metz Cathedral, the publishing house Les Editions du Signe will present a tribute comic book created by François Abel and Charly Damm.
Here is a summary:
Metz. Year 2253. All life has disappeared on earth when Arthur, an extraterrestrial, lands with his spacecraft on place d’Armes and enters the cathedral. In the crypt, he releases the hideous Graoully which, in exchange for its freedom, tells him the story of the building from its beginnings.