As i've worked in this industry in the UK
my dads a cab driver and has owned and operated two cab firms in my life time. i' know abit about this. (since i've worked the radios taken calls helped repair cars and prepped them for council tests and now in my later live designed websites and booking/quotation systems for these his companies)
i can tell you that in essex at least cabs and private hire cars do the same tests and are regulated (i.e. if a drive takes the scenic route you can request his cab license number/car plate number a report him.)
the cars are tested regularly on top of the mot to make sure that they are safe and are in working order and they own of the firm can be held liable for a dangerous car in there fleet.
the drivers have to take health and safe courses so they know how to treat disabled ,elderly and children (some cab firms now have there drivers crb checked before employment. but i'm not sure this is law. )
failure to obey these rules means they can't drive cabs/private hire cars any more and if a firm hires that driver they can be shut down.
Now yes there are those that flout the rules and the forces of completion do some times apply but often they don't because people think it's just a cab they won't do anything and those that flout the rules are the cheapest because it's the only way they stay in business is people who care out cost of the driver being on time and the car being respectable.
As for how this pertains to this article. while I'm happy for private hire cars to exist they should be licensed to the same or similar standard a Cabs with he same accountancy
Although not knowing the rules in France these these not a lot i can say about there level of rules.