It is also worth noting that some, if not most, new cars are not supplied with a spare wheel.
I have a new Citroen and no spare was provided only the emergency 'tyre weld'. This is standard and I believe is the case with other makes Renault, Peugeot etc.
You can of course as an extra (extra cost) purchase a spare. I have done this and it is strange that the manufacturers make the car with a facility to store the wheel??
Apparantly this is quite legal and I would suggest the hire companies are not going to pay for any 'extras'.
So please check any hire car preferably when booking.