First time southern France questions

If you’re comfortable packing up and moving every day or so, or doing daytrips from, say, Avignon for a few days and then moving on, you’ll get a chance to see many places in that region of France. But I hope you won’t be renting the car until you reach someplace in France. Renting in Spain and turning it in in France will likely incur a very sizeable extra charge. Even renting from one place in France and returning it at a different place in France could result in extra one-way fees, but probably not nearly as much as a two-country rental.

The destinations you listed would cover seven of your eight days, you'd be driving a lot and missing a lot. Plus the dropoff fees mentioned above. Instead, how about flying to Marseille to get the car and returning it there, then flying home from Marseille (via Paris if necessary)? That saves the dropoff charge and puts you in a central place for exploring Provence and the Riviera. Carcassonne and Annency are outliers that you might not have time for in just eight days. Nice would also be an outlier, perhaps easier to visit by train from Marseilles. Maybe you could drop the car in Marseille, take a train to Nice, and fly from there instead of Marseille. Lots of ways to do this, but focusing your trip on a smaller geographic area might be wise.

Drop off the Spanish rental rental before crossing into France if you even need one in Spain. Pick up the car after crossing border into France. That is what we have done multiple times with many different countries.

Picking up a car in Spain and dropping it in France will cost you a fortune (hundreds of euros extra)

Take a train from Barcelona to Béziers (2h20 journey with a direct train, < €100).

Rent a car in Béziers (there are several car rental agencies at the station), you are 1 hour drive from Carcassonne or Montpellier (just in between).

If it were my trip, I would fly to Marseilles, book an adorable Airbnb in St Remy and spend a few days exploring the Luberon villages, markets, lavender fields, Roman sights, etc then finish with a couple of days in Paris, or fly out of Nice.

See which destination in France has the best flights from Mallorca and start planning your trip from there. It's unnecessary to fly back to Barcelona and then drive through France.
You will be missing the July, August traffic on the Riviera, but really, you have little reason to rent a car along the Riviera. Since you are looking forward to sowing your empty-nest oats, you may want to rent a car after the Riviera. I like the idea of staying in a small Provence town and visiting the area. I'd drop Carcassonne, Montpellier, and Annecy this trip.

If you do end up in Annecy, consider flying out of Geneva. Much closer than Paris, and probably less crowded, especially with the Olympics so close to your dates. We are flying into Nice and out of Geneva. Both nonstop flights to JFK via Delta..

As I was reading your post, my first thought was that it didn’t make sense to fly into Barcelona and pick up a rental car. Unless airfare is prohibitive, the most logical place to fly into is Marseilles. Have you looked at places like Aix en Provence, St. Remy, and Luberon villages? Such as Gordes, Rousillon, Bonnieux. They are all beautiful, and easily accessible from Marseilles.

Are you spending any time in Paris? If not, then fly home from Marseilles. It’s a long drive to Paris from southern France.

Marseilles is a wonderful city to visit. I love the Le Panier district with its colorful street art. You could spend a night or two in Marseille. Then spend a night or two in Aix. Then 4 nights in St. Remy which is a good base for exploring the Luberon villages.

If you are spending some time in Paris, I recommend taking the train to Paris (from either Avignon or Aix) instead of doing that long drive.

You're right and as others have indicated, you're probably trying to do too much in too short of a time period. Europe isn't Disney...and no matter how hard you try, you can't see it all. Select a manageable trip (3-4 stops) and just know that it will still be there when you go back...not if.

My suggestion for going to France and leaving from Paris... 1) Stop at Carcassonne on the way to Bordeaux ( 1-2nights), 2) Loire River Valley (Ambois 2-3 nights...wine and chateaus) and 3) St. Malo (stay within walking distance of the walled city...Mont Saint Michel 1-2 nights) and 4) Paris (2-3 nights). Paris is the one city where I could spend a week, or more and never get bored. That said, Paris will probably be really, really crowded this year.

Another suggestion for going to France and flying home from Geneva...1) Provence (2 nights), 2) Nice (3 nights) and 3) Annecy (3 nights). We like to slow down as trips go on. Annecy would be a nice place to relax and end a trip. You can either return a rental to the French side (1hr.) of the Geneva airport or take the train from Annecy to Geneva airport (1hr 20min IIRC).

You're still traveling a lot with either itinerary, but you'll be able to see more things. Lots of good day trips from all of these areas, as well. Research all of your destinations thoroughly and build the trip around things you would like to do. Slow down and soak up Europe. It's magnificent.