Expect 50% salary and taxes that will make your eyes water. French bureaucracy is kafkaesque even in 2026.
Other than that I agree I'd love to move there.
But yes, salary before taxes is much lower than in the US. If your goal is to make as much money as possible, either stay in US or move to a different European country (Northern Europe or Switzerland).
You're "not really worrying" ... whilst you are in a job.
There fixed that for you.
As I am sure you are acutely aware US is the home of lay-offs and is generally easy to fire people.
If you loose your job in the US it becomes panic stations because you loose that precious employer-paid healthcare overnight.
Meanwhile in Europe ? Take your time job hunting a new job, healthcare is still free.
Currently, healthcare coverage tend to be better in several European countries when you are jobless... because the system try to compensate the fact you do not have income anymore.
Don't get me wrong, their is many 'flaws' in several European healthcare systems and it is far from perfect. but it tends to be more "human" and less "for profit".