Pierre-François-Léonard Fontaine (pronounced [pjɛʁ frɑ̃swa leɔnaːʁ fɔ̃tɛn]; 20 September 1762 – 10 October 1853) was a French neoclassical architect, interior decorator, designer and artist.

[1][5] A 19th century observer noted the following about their intertwined careers: "It is surprising what a complete mastery these young men in a few years contrived to exercise over the tastes of their day.

In 1799, the artist, Jacques-Louis David,[8] introduced Fontaine to Joséphine de Beauharnais, Napoleon’s first wife.

Indeed, one analysis of Napoleon's impact on the architecture and urban design of Paris states that Percier and Fontaine were the two "most important architects of his reign".

They deployed their Empire style in numerous interior decors and in restoration work on the royal residences of Malmaison, Saint-Cloud, Compiègne and Fontainebleau.

[11][8] One of their major collaborations was the Arc de Triomphe du Carrousel, which was modelled on the Arch of Constantine (312 AD) in Rome and which celebrates Napoleon's military victories.

Fontaine and Percier also pierced the first, western part of the rue de Rivoli, including its distinctive arcades, and built the northern, 'Rivoli' wing of the Louvre, thereby competing the Cour Carrée.

[6] Following Charles Percier's death in 1838, Fontaine designed a tomb for him in their characteristic style in the Pere Lachaise Cemetery.