Itinerary: is it ok ?

Looks good you can go to the beach at St. Malo

The plan looks good! July and August are a very good time to visit half of the places you are planning to see - sure, there are more crowds, but weather will be at its best in fickle Normandy, Brittany and the Alps.

Why the new thread, though?

Looks good to me and I have visited most of these places. Couilliure near Carcassonne is another stop that you might consider. I have not visited there but have researched it and hope to visit. I liked Annecy a lot, Chamonix is also one to consider. The activities like the lifts are better early as it can cloud up in the afternoon. When I visited as a day trip from Annecy we were not early enough. You are lucky to have so much time.

Be aware that Annecy can be very hot in the summer. Look for air-conditioned lodgings, the same as at your other non-Normandy/Brittany stops. You'll have to be unlucky to need a/c in Normandy or Brittany, but it can happen. I had a few really hot days in Brittany this July.

Sarlat ( or near) for 4 nights

Carcasonne ( near) one night

Sarlat is a great location to make day trips in the region, plenty of restaurants when you're back in the evening. I had a very short stop in Beynac in May and it's on a bucket list for a longer visit. There is a castle at the top that Richard the Lionheart occupied for a few years during the Hundred Years War. The town was also the backdrop for the movie Chocolat. It's a beautiful town. I didn't stay long enough though to know if it's worth an overnight stay, but it's on the list for another visit.

I would recommend staying right in Carcassonne overnight. It will be crazy crowded in the summer, but you can have the place to yourselves in the evening and early morning. I highly recommend you get up for sunrise along the east walls. It's worth it. We stayed at Hotel Montmorency which is a 2 minute walk to the main gate.