Hôtel de Lassay

You can read the Hôtel de Lassay like a case file: names that recur, dates that line up too neatly, and architectural choices that only make sense when you know who wanted what. The current resident is political in the most literal way—Yaël Braun-Pivet, President of the National Assembly since 28 June 2022—but the mansion’s true mystery is how many hands shaped it before it settled into its parliamentary function.

A mansion built from competing clues

The trail begins with Léon de Madaillan de Lesparre, marquis de Lassay, who commissioned a plan for a private townhouse in 1722. He engaged an Italian designer, Giardini, who died the same year, forcing the project to restart before the stonework could fully commit to one vision. That first clue matters because it explains why the building’s creation reads like a relay rather than a single-author masterpiece. Soon after, the work is tied to Pierre Cailleteau, known as “Lassurance,” who died in 1724. Then the responsibility shifts again—to Jean Aubert and Jacques V Gabriel. Even now, the balance of authorship is debated: today it’s estimated that Aubert was the principal author, and that the same authorship logic applies to the adjacent Palais Bourbon, the seat of the lower house of Parliament.