A French carol (which you needn't sing) from the 15th c. is "Bel astre que j'adore", the tune of which is "Charmante Gabrielle"; see this thread/message for a link to a sound clip:
Les Chansons de la France: http://www.mudcat.org/thread.cfm?threadid=39187#2517624

The second tune in the sound clip is another possible candidate, "Pe trouz war an douar" (What is the sound[, the song which I hear]?), which some sites refer to as 17th c., though I haven't tripped across any details in my cursory exploration.

Sound clips for both may also be found on YouTube, and several sites have scores.