Hôtel de Mercy-Argenteau, Private mansion in 9th arrondissement, Paris, France.

The Hôtel de Mercy-Argenteau is a six-storey stone building at 16 bis boulevard Montmartre. Its long cream facade has eleven bays, a slightly projecting three-bay central section, a rusticated ground floor with an arched doorway, two upper storeys behind a continuous wrought-iron balcony, and a mansard roof with dormer windows and a second iron balcony. A red awning with a white star marks the ground-floor restaurant on the right.

Jean-Joseph de Laborde commissioned architect Firmin Perlin to design and build this residence in 1778. After its completion, Laborde sold it to Count Mercy-Argenteau, an imperial ambassador.

The building's name comes from Count Mercy-Argenteau, imperial ambassador to Paris from 1766 to 1790, who bought it from his friend Jean-Joseph de Laborde. In the 19th century the noble floor housed a fashionable circle, the "Grand Cercle". Since 2024 the École des arts joailliers de Van Cleef & Arpels has held temporary exhibitions on jewellery and adornment there.

The building is privately owned and normally closed to the public, but certain areas may open during special heritage events throughout the year. Check ahead to learn about any scheduled public access opportunities.

Between 2013 and 2019 the building housed Mozilla's Paris office, where Firefox, Rust and Servo were developed; internet and free-software events were held there regularly. Since 2024 the École des arts joailliers de Van Cleef & Arpels has used it for temporary exhibitions on jewellery and adornment.