What a lovely song to get this much attention! I have a copy of Anthologie de la Chanson Francaise (La Tradition des Trouveres aux grand auteurs du XIX siecle). I think we might consider this a safe source! Confirmed: words by Jean-Pierre Claris de Florian and music by Schwarzendorf a.k.a. "Martini". Florian, by the way, was a protege of Voltaire's and quite admired in the salons. He was considered perhaps the next La Fontaine. Martini wrote a good deal of music, but would not be known today were it not for this piece. Furthermore (are you still with me as I translate?), "Plaisir d'Amour" had a sort of double career in that it was as popular in the salons --where the hoity toity people met--as in the more folk milieux. Composer Hector Berlioz did an arrangement for orchestra in 1859; concert singers included "plaisir d'amour" as part of their repetoires from there on. The lyrics from the Andres Magre message agree with my book.