Best car rental companies for roadtrip to Rome from Barcelona?

Hey! So I’m planning to take a roadtrip with my family on December, starting from Barcelona to Rome and back to Barcelona, we mostly want to pass through the French Riviera and make some stops on some towns until we get to Rome. My question is if you have any advice on which rental car compsnies are the best, do I need a special license to drive over there ( I’m from Guatemala) and if there is any problem crossing the border that we should know.

Thank you very much for your help!