Desfontaines spent two years in Tunisia and Algeria, returning with a large collection of plants. He wrote Flora Atlantica (1798–1799, 2 vols), which included 300 genera new to science. In 1786, he was appointed professor of botany at the Jardin des Plantes, replacing Lemonnier. He later became director of the Muséum National d'Histoire Naturelle, was one of the founders of the Institut de France, president of the Academy of Sciences, and elected to the Légion d’honneur.