I just booked a car in Corsica. I carry an IDP when I rent a car in Europe. I found this language in Auto Europe rules:
"An International Driving Permit is required in addition to a National Driver's License if the National Driver's License you or any of the Additional Drivers hold is not clearly identifiable as a Driver's License, e.g., it is in a non-Latin alphabet (e.g. Arabic, Chinese, Cyrillic, Japanese)."
I thought this is interesting and might explain, to some degree, why I have never been asked for an IDP at a rental car agency in Europe, even when I have offered to show them mine, they have declined.
Of course this does not mean that you won't be asked for one, but it appears that Auto Europe will not insist on one if yours is in a Latin alphabet.