Pros and cons of flying from Marseille or taking the train from Avignon: you check into a small, easy-to-manaage airport in Marseille, changing planes at CDG. You'll still go through passport and a second security control at CDG. However, you have to be on Skyteam (Air France/Delta/KLM) for this to be on one itinerary. One inconvenience is that your flight from Marseille could be very early in the morning in order to make the CDG connection. Sometimes the regional flights are delayed and passengers barely make their international flight, or even miss their flight and have to be re-booked. But you will be put on the next available flight.
If you take the train directly to the airport from Avignon, where you return your car., you are at the airport the night before. These trains are frequently delayed anywhere from a few minutes up to two hours, so it's important not to leave Avignon too late. Check in and passport control at CDG could have long lines.
In both cases, you have to lug your own suitcases back and forth from the hotel the night before. I didn't mention Nice because it's over two hours away on the Côte d'Azur, not in Provence.
We had to make this choice for our upcoming trip to the US. Our regional airport has always had a mid-morning AF flight that coordinated with our US flight. However, local flight time was changed, putting us on a 6 am domestic flight. My husband said absolutely not. So we are taking the train the afternoon before, staying in a Paris hotel next to our train station, taking a taxi to CDG and flying to the US in the afternoon. I chose Paris because a taxi takes us directly to our terminal door. At my age, I'm tired of luggage schlepping.
