Not sure if that could help you or not, but try to ask people who are into french cars and especially old Renaults, Alpines and Gordini cars. The same brand that was making them made lots of them in 3-lugs and 4-lugs pattern for these cars and maybe they could help you find a set of these as they're often looking to find some of them.
I think it won't be easy, this set that was for sale at the European Bug-In was the first time I've been able to actually see these wheels. I knew they existed but I have never even seen old photos or catalogs showing them.
Here are a couple of links (in french but you can translate it) about the woman who created thoses wheels :
https://webzine.bm-lyon.fr/spip.php?page=fabrik_portrait&id_article=534http://passionnsujcb.canalblog.com/archives/2011/04/19/20934787.html