Leonard Sylvain Julien (Jules) Sandeau (1811-1883) was a French novelist. He met George Sand, then Madame Dudevant, at the house of a friend, and when she came to Paris in 1831, they had a relationship. The intimacy did not last long, but it produced "Rose et Blanche" (1831), a novel cowritten under the pseudonym J. Sand, from which George Sand took her famous pseudonym.