The royal room, with the lounge meeting which follows, is particularly distinguished by its carved wood, painted and gilded, and its stucco ceiling. The richness of the decor is accented by four piers of ice that reflect to infinity the decoration of the room. The royal opens alcove at the back of the room, facing the three windows overlooking the River Ill, between fluted columns with Corinthian capitals connected by a balustrade. Three tapestries, part of the set of eight tapestries of the eighteenth century on the history of Constantine and acquired by Cardinal with his niece, the Duchesse de Mazarin, are stretched in the alcove. Robert de Sery is the author paints in top-of-door made from the Raphael Loggia at the Vatican, while Tables piers of window are original PI.Parrocel.