Regarding the taxes, I will say what I always say: yes they are higher than in the UK, but you get more. So you need to compare what you're getting, otherwise the comparison is meaningless. I am working in the UK, where I paid around 35 % of taxes, so quite lower than France, where it would be closer to 50-55 % I think for my salary. But then, I get shitty health care and essentially no pension. And if I have kids, I will have to pay a lots of money to get them a decent school. I would love paying 15-20 points more taxes in exchange for that in the UK.
IMO, the main issue in France is more the education system and how the incentives are highly biased toward going to a big company. The whole society is highly biased against failure, and the only path to a 'career' is through 'soft' areas. I am just over 30 and my parents don't understand why I am still doing engineering instead of 'managing' people, for example. This is the main reason why I have been leaving outside France for the last 8 years or so, not taxes.