The Palais Bourbon and Hôtel de Lassay were built simultaneously, from 1722 to 1728, on land acquired by the Duchesse de Bourbon in 1720, part of which she ceded to her lover, the Marquis de Lassay. Four architects (Giardini, Lassurance, Jacques Gabriel and Aubert) succeeded one another in directing the work.
After the duchess's death, the Palais was acquired by Louis XV, who ceded it to the Prince de Condé in 1764. He entrusted Le Carpentier and then Bellisard with extensive enlargement work: the courtyard of honor was surrounded by buildings extended to the west as far as the Hôtel de Lassay, which had been purchased in 1768 from the marquis's heirs.
Confiscated in 1791, the palace was declared "property of the Nation". In 1794, it housed the future Ecole Polytechnique, before being assigned to the Conseil des Cinq-Cents in 1795. During the Restoration, the Prince de Condé wanted his property back. He regained possession of the Hôtel de Lassay, but was obliged to rent the Palais, transformed into a hemicycle, to the Chamber of Deputies "under a 3-year lease". The State became the definitive owner of the Palais Bourbon in 1827 and the Hôtel de Lassay in 1843. After acquiring the Palais Bourbon in 1827 to house the Chamber of Deputies, architect Jules de Joly spent five years overseeing the transformations that would give the building its current appearance.
