anna, thanks for that. I appreciate the tax systems are different.
Why is the cost of the employee to the employer is relevant? In UK, as you probably know, we only take the last 3 into account.
38 take home based on a 100 salary is quite a high rate of tax/social security - 62%, compared to 40% in UK - allowing of course for that fact that yours is just an example.
Presumably the higher rate tax payer is also taxed at the same high-ish rate?
In our case, I appreciate if I was a lower income tax payer (22%) under the current UK system, I would be discentivised if I found out I had to pay 40% or 62% instead. But I currently already pay the highest rate (ie 40% or 62% in your example) and I am not disincentivised to work. So not sure why a high earning French woman is disincentivised as you describe, as opposed to a lower earning French woman if she were under the UK system.
Of course, I am comparing apples and oranges. If it is too complicated to transpose, don't bother