It's not exactly a level playing field, with a limited number of taxi licenses being bought and sold on the open market for around 200k-250k. No surprise they're not happy and want to recoup their investment…
The Rude Baguette did a nice article on how the Paris taxi market works, which explains a lot: http://www.rudebaguette.com/2013/08/07/anatomy-of-the-paris-...