This will become easier to compare as income tax will soon be taken directly from the payroll like most other countries.
However it's important to note that many people don't actually pay that much income tax in France, or at least nowhere near the 20% to 40% number you're giving.
If you're married it depends on your spouse revenue, whether you have kids or not (especially between 0 an 3 yo because you get a tax credit on daycare, etc...)
I think the biggest difference between a Software Engineer in France and UK or Germany is not the taxes, but that the gross salary would usually be much lower in France.
However it's important to note that many people don't actually pay that much income tax in France, or at least nowhere near the 20% to 40% number you're giving.
If you're married it depends on your spouse revenue, whether you have kids or not (especially between 0 an 3 yo because you get a tax credit on daycare, etc...)
I think the biggest difference between a Software Engineer in France and UK or Germany is not the taxes, but that the gross salary would usually be much lower in France.