I would recommend the following options:

1. The most famous and probably the best resort in the Atlantic South of France - Biarritz. A beautiful city with a history, a stunning beauty bay, quiet streets, a thalassotherapy center, a wide range of hotels, the possibility of an extensive excursion program (this is Aquitaine, and you can go to vineyards, you can go to Spain in San Sebastian).

You can get there by train from Paris, and by plane, there is an airport in Biarritz.

2. La Baule / La Baule in Brittany. About 3, 5 hours from Paris on a fast and comfortable train, without transfers. Which is very convenient. The cost of a railway ticket to one side is about 60 EUR per person.

The stunning beauty of the bay, the length of the coastline is about 9 km. The beach is sandy and wide. Very beautiful and well-groomed embankment, special paths for cycling, silence, pine trees and clean air. Horseback riding right on the ocean. It looks exciting. There is a market and supermarkets in the city.

The only thing that must always be considered when resting on the Atlantic is the water temperature. At air temperature, for example, in August, + 28-30 ° C, water temperature + 20-21 ° C.

In addition, La Baule is one of the most famous thalassotherapy centers, so it's possible for adults to take care of themselves and pay attention to themselves.

Of the sights you can visit, for example, the famous Abbey of Mont Saint Michel, located 200 km from La Baule. It is also interesting to visit the stunning Pugh du Fu park, located in the Nantes area, or the castles of the Loire.

But the main trump cards of La Baule are nature, air, silence, beaches and a bay of stunning beauty.

3. Deauville in Normandy. Elite place, good hotels of different categories, close to Paris (about two hours on the road by train), developed infrastructure, excellent beaches, casinos, boutiques, nightlife, thalassotherapy center. Everything for a beautiful and active holiday. The excursion is all tied to the North of France - Normandy and Brittany: Mont Saint Michel, Saint-Malo, Rouen, Honfleur, Etretat and other wonderful places are waiting for you.

4. Arcachon, Aquitaine. A unique place, an abundance of sand, the largest dune in Europe. The only negative - very few hotels 4-5 *, mostly "treshki."

The main area in Aquitaine is visiting vineyards, tasting, visiting farms. The capital of Aquitaine is Bordeaux, and is also nearby.

5. La Rochelle / La Rochelle. The resort is located on the shore of the Bay of Biscay in the Poitou-Charentes region. Both the air and the ocean are warmer here than in the north. Beaches are sandy, broad. Only 3 beaches: Chef de Baie, La Concurrence, Les Minimes. La Concurrence is located in the city center. Many yachts, boats (the same port).

But, in my opinion, The beach and the bay of La Baule, Biarritz and Deauville are the best.

La Rochelle is a port city with its own history. The old port, the house of Henry II, stories with the adventures of the Musketeers, the city gates, very beautiful streets. Next to La Rochelle is the famous Fort Bayard. In addition, you must visit the Aquarium of La Rochelle: 2 floors, 12 thousand marine animals, there are sharks. Also from La Rochelle, you can make a trip to the Futuroscope park.