I don't know how things are in France, but in the USA if you are fortunate enough to have a company-sponsored retirement plan, your money is typically invested in the stock market, with no guarantee that you will have $xxx/month in your retirement years: Maybe you will get lucky, but maybe you will end up with nothing. But regardless, the company managing the retirement plan always collects their fees.
Regarding taxes in the USA, in Why "A" Students Work For "C" Students, Robert Kiyosaki mentions this:
As Kiyosaki sees it, the real difference between the two men is that Romney has a more sophisticated understanding of money, and gets most of his income from investments, which are taxed at a much lower rate, whereas Obama has an employee's understanding of money, but employees pay more in taxes.
Although in some ways his books are not very well-written, are filled with out-of-context quotes from famous people to support his statements, and contain much which is questionable, Kiyosaki also has a much more broader view on the creation of wealth, going well beyond common bits of wisdom such as paying off credit card debts and diversifying one's investment portfolio. And he makes the case for investing for income rather than for capital gains, which is a point of view which I had never seriously considered before, but maybe I should.