Has anyone noted the hilarious irony that Macron is a native of Amiens in the depressed postindustrial north of France, while Le Pen had grown up and currently lives in the posh western suburbs of Paris, in particular Neuilly, Saint-Cloud, and La Celle-Saint-Cloud, basically some of the wealthiest towns in the country. And her father is from Brittany, a region which showed her very little love!
I wonder how these very rich areas would vote in a hypothetical Le Pen vs. Mélenchon Round 2 as these areas obviously can't stand either of them? I imagine they'd hold their noses and vote en masse for Le Pen as her brand of far-rightism is less probably far less threatening to the bourgeoisie types of Neuilly-sur-Seine than Mélenchon's brand of far-leftism. They'd definitely still vote in a landslide against the RN in the legislative elections though.
Another good map that @tuxfak did yesterday. Obviously this is not a full vote, but a comparison of 20-ish percentages, but it is not hard to imagine the final result looking somewhat like this given abstention and differing appeals. It looks like the well-off areas went for Melechon if then were part of a major metropole, and went for Le Pen if they are outlying.
Well that's obviously excluding where voters would go if forced to pick between the two. In Neuilly-sur-Seine for example barely 11% of voters picked Le Pen or Mélenchon in the first round, meaning that there would be 89% up for grabs. I'm not an expert on French politics but I struggle to see rich bourgeoise formerly reliable LR voters ever voting for someone like Mélenchon even if the alternative was Le Pen. These people would certainly be more threatened by Mélenchon's economic platform than Le Pen's and as others have commented on here before these voters aren't exactly known for their social progressivism either.
Maybe wealthy up-and-coming yuppy type areas would back Mélenchon over Le Pen, I'd have to defer to someone with more knowledge than me. But I'd be shocked if there is any scenario where the 'old money' super wealthy areas voted for Mélenchon regardless of who his opponent was.