Hôtel Pillet-Will, Private mansion in Faubourg-Saint-Honoré, Paris, France.

The Hôtel Pillet-Will at 31 rue du Faubourg-Saint-Honoré, in the 8th arrondissement, keeps only its street building from the 1887 Neo-Louis XV mansion; the rest was rebuilt in 1967. The cream stone facade has five tall windows per floor, stone balconies, slate mansard dormers, and a carved arched portal with deep red doors and a stone head above.

Built in 1718 by Pierre Cailleteau, called Lassurance, for Louis Blouin, Louis XIV's first valet de chambre, the house passed to Gabriel Michel in 1753 and was remodelled by Legrand and Molinos as the hôtel de Marbeuf. The Concordat was signed there on 16 July 1801. In 1884 the banker Pillet-Will bought it and had the neo-Louis XV mansion built in 1887; the Japanese embassy demolished it in 1967, keeping only the street building.

Since 1967 the Japanese ambassador has lived in a modern building set between courtyard and garden, raised behind the surviving 18th-century street wing. The embassy bought the property in 1965 and demolished the old mansion, keeping only the facade on rue du Faubourg-Saint-Honoré. The residence holds Jean Prouvé curtain-wall facades and Charlotte Perriand furniture.

The mansion sits near the Champs-Élysées and is accessible by metro stations Miromesnil and Concorde on lines 1, 8, and 12. Visitors should note this is a private residence with limited public access.

The 1927 listing covers only the street portal and its door leaves, not the whole building. The 1887 door leaves were reused from the Hôtel de Vicq, demolished in 1883 at 203 rue Saint-Martin. The 1967 replacement behind the facade, the Japanese ambassador's residence, has curtain walls by Jean Prouvé and furniture by Charlotte Perriand.