I received several fines claiming non-authorized circulation after ten months for incidents both in rome (150 euro) and florence (115 euro) and possibly waiting for more. They claim this is enforced via a video system that take time to analyze. I complain since it is not possible to "learn" from the offense at the time of the incident (compared to receiving a fine from a policeman) and I finish repeating the offenses all along the visit. I don't recommend visiting italy with a rented car, otherwise need to spare some 1000 euros extra. It is strange however since I used cars also while visiting spain and france and never got a single problem.