I've left France (I'm french), and now live in Malta, because of the Bad and the Ugly. France has high taxes (and 50% social contributions), very anti-entrepreneur and ultra-bureaucratic mindset, a sinking economy, a vastly anti-libertarian political landscape, and a high cost of living vs. quality of living.
If you're tempted anyway, Good Luck.
I live in Nantes right now (after 7 years in the Netherlands) and the quality of living is great, at a fraction of the price in Paris.
Second, not everybody is a libertarian, so I'm quite OK with what you call "anti-libertarian landscape".
Bureaucratic mindset : Apart from Malta, have you ever lived anywhere else in Europe ? I don't know the bureaucratic mindset of Malta, but I can say that I did not find a great difference between France, the Netherlands and Germany for instance.
When I hear "France has great tax credits systems for startups", I think "if you spend months in paperwork, maybe". That's what I call a bureaucratic hell.
As for being a libertarian, I guess it's the case of a majority of entrepreneurs. If one enjoys government control, he's probably not an entrepreneur...
Who wants a 3500 page labour code like we have in France? Ever changing laws? New regulation and a new tax every month?