15 day PTO and the 40h week was brought by a conjunction of union work, general striking, and the first elected socialist government in France.
I dunno when the EU laws were created, but the 4th and the 5th week of PTO were also brought by unions (one with the help of q socialist government). The other 14 days (we have 39 total PTO in France, 14 of those can be redeemed as money basically) i don't know where they came from.