I have a copy of the sheet music - Bayley and Ferguson's Festival series (2 Great Marlborough Street London or 54 Queen Street Glasgow) This edition is edited and arranged "with Pianoforte accompaniment from the original figured bass" by Arthur W. Marchant, copyright 1922 by Bayley and Ferguson, price 2/6 net! Of course it does mention that the original composer was Martini (1741-1816) It is in the key of F going into F minor for the middle bit. The French words are exactly as Andre has typed them, and there's an English translation which is far from literal and a long way off Joan Baez's version!
As far as I can remember I picked it up from a bookstall on the South Bank of the Seine some years ago! I think I also got O Sole Mio at the same time.
By the way, do other people find odd things in their piano stools? I found a couple of Australian Christmas carols the other day, all about Santa jumping in a swimming pool: I've no idea how they got there! When I sang them someone said I should put them back and shut the lid firmly!
(?Subject for another thread?)
Tattie B