This identifies a problem: PhD students are treated badly both in terms of working conditions and pay. The solution isn't to abolish the PhD. It's to have better working conditions and pay! PhD students should be employees with all of the protections this gives them. They should have unions (I have been both at union and non-union shops, you want to be in a graduate student union). PhD students should benefit from th…
That said, PhD students (and researchers) are still poorly paid (though PhD stipends are being raised over the next few years), and though France has a legal 35 hour work week, informal pressure of academia means that tends to be thrown out the window.
There are legal requirements on graduate schools that help protect students from abusive advisors or other abuse within their laboratories, of course since the research world is small, it remains to see how effective they can be.