If you find one let me know! It is crazy that Sixt almost double the price of a weeks rental by wanting €20 a day, Hertz are a bit better. Untill now I have booked with Hertz without winter tyres and they have mostly been fitted,on the one time they weren't they did not have any cars with them ! Last Winter I read about people being refused a car unless they paid the extra so maybe that will no longer work