Jean-Jacques Rousseau (1712-1778) is well known as a writer and philosopher, but he was also a musician and composer, but considered a minor.
In the quarrel between music of Italian influence and music of French influence (Rameau), he chose Italian, and wrote in "Lettre sur la musique française" "that French singing is nothing but a continual barking, unbearable to any untrained ear; that the harmony is raw, without expression and feeling only its schoolboy filling; that the French airs are not airs; that the French recitative is not recitative. I conclude that the French have no music and cannot have it; or that if they ever have one, it will be too bad for them.

And yet, he composed a few comic operas in French, the most famous of which is "Le Devin du Village" (1752) for which he also wrote the libretto. This opera received a prodigious success, so much so that King Louis XV sang Colette's aria at any time during the day, "in the most false voice of his kingdom".

Several CDs exist of this opera, and you can also find the full version on Youtube