Taxes are high because the pension system is managed by the public sector and are financed by taxes. In a country when pension are a matter of personal responsibility, they are paid to private companies.

So you see, when a french person pay for their pension, it's taxes. When a person from another country pay for their pension to private companies, it's GDP. In the latter case, you have the additional freedom of not paying anything (especially if you don't make enough) and then hope that you die before retirement. I would not call this freedom though.

Try to think outside of the conventional wisdom which is completely skewed