The French culture on this is very different, people simply don't talk about money and salary.
I found a starting salary survey in a business magazine that indicated graduates of the top 5 engineering schools are getting about 40-55K/year
35-40k for master's degree from everywhere else.
If you don't have a master's just forget about it ^^
But that was not the point, the point was that people talk about "raw", or "after taxes", while it does not mean the same. In France when they talk about "income after taxes" (~23% salary taxes), it is before the equivalent of US Federal+State taxes. These ~23% are about "social contribution" (mandatory healthcare, retirement, unemployment, etc.). Only then, the income taxes are computed on what remains, depending on your family situation (having children impact a lot in France compared to the US). For a single person it can be up to ~ two-months salary.
(City taxes exist there as well after that).
I hope their system proves sustainable in the long run... I wish I had a way to participate in it (I could apply for the visa, I suppose), but it would be difficult for my US academic wife to break into French academia[2] at a suitable level.
[1] In a bad year, we're talking $13K in deductibles for a family of four on an average insurance plan.
[2] Now that I think about it, she studies French domestic politics. Hmmm...