Originally Posted by
Will Coe
1. Would I be allowed to rent a car with a French driving licence but w/o an international driving permit?
Most car rentals in the US require an IDP as well, but so far I've never been asked one. Some agencies have issues reading an European driving license (both the new and old types). If they enforce their policy, you'll be stuck without a car.
Originally Posted by
Will Coe
3. Are some of them known to accept foreign driving licences not written in English but using Roman alphabet? And if so, which ones?
I would worry more about being stopped by police and not being able to give them a driving license in their official language (i.e. English).
In short: Get yourself an IDP. I took me 2 minutes to get one and it puts you on the safe side. (Do however pay attention what IDP is accepted in Australia as there are multiple IDPs.)