Unfortunately I know little about French or German composers and song to know what would be traditional. Is there any site devoted to either language for song lyrics. I was able to find lyrics to a couple of the songs. Some of them listed a name. Have a look

Susser die Glocken nie Klinge
Fete De Rois Mages
Les Rois Mages
Fete de Rois Mages

With the names, you might be able to do research on when they were written from when the author/composer lived.