Parking (not counting the city center) will cost €0.7-1 per hour. In some historic city centers, entry is completely prohibited. And in Rome there is a zone for which you need to purchase a special license to drive. To get to Venice, you need to leave your car in a parking lot and transfer to a water tram. In Naples, Rome, and Florence, driving a rental car in the center is a terrible ordeal for the nerves.
Despite the fact that Italians are famous for their dashing driving, you need to be careful behind the wheel - a fine for exceeding the speed limit by 30 km/h is €500, running a red light is €100. If you don't want to lighten your wallet by an even larger amount and also get acquainted with the local judiciary, you shouldn't offer bribes.
Good auto news for those heading to Spain: parking here is much easier than, for example, in France. And in small resort towns, it's always easy to find a free spot. Problems arise only in areas with many attractions: near La Rambla and close to the Sagrada Familia in Barcelona, for example. Or on the promenades near the beach of such popular expensive resorts as Marbella. But even there, after circling around, you can find a spot. Spanish police are remarkably friendly. If you get lost, the best way to find your way is to approach a police officer. Most likely, he will personally show you the way by asking you to follow his car. And this kindness is easily explained - he doesn't want obstacles in his area.
In France, taking a car for trips along the Côte d'Azur is considered economically disadvantageous; traveling by train is much more economical. But many still take cars. The trip from Nice to Cannes on the toll motorway takes 10 minutes and costs €3.8. The road along the coast is free, but full of populated areas and traffic lights, resulting in a journey of 1.5 hours and a lot of gasoline. At the same time, as 'Voyage i otdykh' notes, it is precisely such detours that allow you to wander a bit through the provinces - since toll roads in France are often surrounded by high concrete barriers, and you are unlikely to see anything besides them and a mass of various cars.
In the evenings, you can spend hours circling in search of a parking spot in the center of cities like Nice or Cannes. The chances of getting a free parking spot for the night are virtually zero, paid street parking is usually also full. There are two options: either 'sleep' in an underground parking lot, which costs at least €8-10 per night (a day will cost €20-26; the daytime rate is about €1.7-2.5 per hour depending on proximity to the center or beach), or break the rules and leave the car where it's not allowed, risking finding a ticket on the windshield in the morning.