Hôtel du Plessis-Bellière, Historical mansion in Place de la Concorde, Paris, France.

Hôtel du Plessis-Bellière is a private mansion at 6 Place de la Concorde, built in 1776 by architect Pierre-Louis Moreau-Desproux behind Jacques-Ange Gabriel's western colonnade. Its pale stone facade has a symmetrical arcade of round-headed arches at ground level, two upper floors of rectangular windows, and paired classical columns carrying an entablature and a roof-level balustrade. Since 1901 it has housed the Automobile Club de France together with the adjoining Hôtel Cartier.

In 1758 Louis XV commissioned Jacques-Ange Gabriel to build two identical facades flanking Rue Royale; the western plot was divided into four lots after the Mint was moved to Quai de Conti. The lot at no. 6 was built in 1776 by architect Pierre-Louis Moreau-Desproux for David-Étienne Rouillé de l'Étang, who had bought a royal secretaryship in 1765. His niece Adélaïde Piscatory de Vaufreland brought it to Emmanuel Pastoret, chancellor under the Restoration; their descendant Marie de Pastoret, marquise du Plessis-Bellière, died childless in 1890 and left the house to Pope Leo XIII, a will contested by the Rougé family and the State and followed by auctions in 1897. The facade has been a listed monument since 1923, and since 1901 the house has been occupied by the Automobile Club de France.

The mansion's name recalls its last private owners: Marie de Pastoret, who died in 1890, was the wife of Hervé de Rougé, Marquis du Plessis-Bellière. She left her estate to Pope Leo XIII, asking that the house become the apostolic nunciature; the will was contested by the Rougé family and the State, leading to celebrated auctions in 1897. The original interior decoration was dispersed at auction in 1898 and is known through the sale catalogue.

The mansion stands at no. 6 Place de la Concorde, in the row behind Gabriel's western colonnade, next to the hôtel Cartier at no. 8. Its facade, classified a monument historique since 1923, is seen from the square; the interior belongs to the Automobile Club de France and is not open to visitors.

The building was replicated in Philadelphia by Horace Trumbauer and Julian Abele, where it now houses the Free Library of Philadelphia. The same city holds a second replica of the matching Hôtel de la Marine, the counterpart across Rue Royale. The marquise du Plessis-Bellière, childless, left the mansion to Pope Leo XIII in 1890, asking that it become the apostolic nunciature; the will was contested by the Rougé family and the State, leading to famous auctions in 1897.