Sainte-Maxime is a nice seaside resort, which is very active and full of tourists during the summer. Its beaches are very wide and clean. Sainte-Maxime is located on the bay in front of Saint-Tropez.
There are 2 large parking lots at the marina: GPS 43.306288, 6.641340 and GPS 43.307808, 6.639535, and the third in the town itself (GPS: 43.309322, 6.638736). Nearby the bridge on the river Préconil you can find the fourth parking lot (GPS: 43.307285, 6.633086).
Sainte-Maxime has a very pleasant marina, which is also an excellent starting point in order to make a trip to St. Tropez. Why bother driving a car to Saint-Tropez on the ever-crowded roads, and later being already in the town to get nervous while searching a free place in the parking lot? Many boats and ferries sail to Saint-Tropez from Saint-Maxime, so you really should get one of them to enjoy the journey in a comfortable environment. The boats depart almost every hour in the morning so you can leave your car in the parking lot in Sainte-Maxime, and return back at the evening. Return ticket prices are about 13€ for adults and 8€ for a child. More details are available online or at the very boat-keepers in the marina.
Just next to the marina there is a very nice and wide beach Plage du Centre Ville (A; GPS: 43.307726, 6.636022). From the beach you can see the town of Saint-Tropez, located on the other side of the bay. After spending time on the beach, you can also go to the town. You cross the street at the roundabout (GPS: 43.308569, 6.638559) next to the bar Café Maxime, which by the way is a good place to eat or drink something. Then you go right, walk about 100 meters, and then on the Place Victor Hugo (GPS: 43.308022, 6.640153) you enter the Rue Courbet street. The center is located at the small square Place du Marché (B; GPS: 43.308409, 6.640729). You could then for example visit some shops or stroll not too many streets.