Hôtel de Brancas, Private mansion in the 6th arrondissement, Paris, France

The Hôtel de Brancas at 6 rue de Tournon presents a pale ashlar facade with a tall arched portal, its double door set deep, crowned by a triangular pediment with two reclining sculpted figures on the slopes. A grilled window sits left of the portal, and a balustrade with small pillars tops the long plain wall to the right. The central arch opens onto an inner passage.

Pierre Bullet designed the hôtel, built 1710–1713 for Jean-Baptiste Terrat, marquis de Chantosme, chancellor to the duke of Orléans, on a site bought from Nicolas Renouard de Chanteclair. In 1719 financier Jean-Baptiste Petit-de-Saint-Lienne bought it from Terrat's heirs for 391,863 livres, then sold it to fund the château de Renay near Vendôme. From 1733 to 1742 it was leased to the Académie royale d'équitation, where François Robichon de La Guérinière taught riding. The duc de Brancas acquired it in 1775; it was listed as a monument historique on 23 July 1970.

The building's name comes from the de Brancas family, a Provençal lineage; the Duke of Brancas, lieutenant general for Provence, bought it in 1775, though it is also called Hôtel de Terrat after its first owner. Since the 20th century it has housed the Institut Français d'Architecture, and the ground floor on the street holds the Librairie Renouard and Éditions Henri Laurens.

The mansion stands at 6 rue de Tournon, in the 6th arrondissement, a short walk from the Luxembourg Gardens and the Sorbonne. It now houses the Institut Français d'Architecture. The entrance portal, staircase, salon and boudoir are listed with the facades and roofs since the classification of 23 July 1970, so the street front and gateway are the elements to observe from outside.

The building is also called "hôtel de Terrat" after its first owner, Jean-Baptiste Terrat, marquis de Chantosme, who bought the site from Nicolas Renouard de Chanteclair. In 1719 the financier Jean-Baptiste Petit-de-Saint-Lienne paid 391,863 livres for it, then sold it to fund his purchase of the château de Renay near Vendôme.