René Louiche Desfontaines was a French botanist.
Desfontaines was born near Tremblay in Brittany. He attended the Collège de Rennes and in 1773 went to Paris to study medicine. His interest in botany originated from lectures at the Jardin des Plantes given by Louis Guillaume Lemonnier. He excelled in his new interest and was elected to the French Academy of Sciences in 1783. He was also a member of the Académie Nationale de Médecine.
Desfontaines spent two years in Tunisia and Algeria, returning with a large collection of plants. He wrote Flora Atlantica, which included 300 genera new to science.
In addition, he worked also on ornithology, and presented the findings of his expeditions to Africa for one of the Memoires de L'Académie Royale des Sciences. Although the Mémoire corresponds to the year 1787, it was not published until 1789 by L'Imprimerie Royal as part of the Histoire de L'Académie Royale de Sciences.