The bathroom, completed first in 1924, has all modern comforts in fine, costly materials such as marble, stucco and antique green-patinated bronze. The bathroom appliances and the two display cases next to the mirrored doors on either side of the washbasin are in Hauteville marble. Part of the walls are in stucco and the bas-relief in the alcove, sculpted by Paul Plumet from a drawing by Rateau, depicts a doe and a stag in woodland.
The floor is laid with black, white and yellow Sienna marble, diamond-patterned or plain depending on the position of the appliances. The patinated bronze taps represent pheasants, daisies and pinecones. The corners of the marble panels partially covering the walls are fitted with bronze angle irons decorated with foliage and daisies.