Thank you, "Guest," for the comment on how "Renaud" fit in with a postwar search for simplicity. (That's rather earlier than the renaissance of interest in rural regional music that took place in the 1970s.) I believe the other two ballads often cited as medieval survivors are "La blanche biche" and "Les métamorphoses." There can be an over-emphasis on the ballads' magical elements when talking about their antiquity -- I am skeptical of suggested connections to druidism! But interest in magical stories is more of a contemporary Anglophone thing than a French thing, isn't it?