wow, indeed you discovered many singers and all different
from Piaf to Stromae, that's a long way
you should also try Patricia Kaas, Zazie, Pascal Obispo and well we have loads.
The French singer that is doing well abroad at the moment is Indila with her big hit Dernière danse
Concerning Mylène Farmer it's weird, some people I know abroad don't care about her, as you and some others were mesmerised from the very first note they heard
... She has a special "universe", you're in it or you're not in it
https://www.youtube.com/watch?v=K5KAc5CoCuk