The huge hydrangeas bowing down to the powdery white sand are the same kaleidoscopic tones of pink, blue and lavender as the sun fading on the wave-dappled inlet just steps from the terrace at Chez Hortense. Across the way, a mile distant, the Dune du Pilat, the largest sand dune in Europe, has a spectacular lunar glow too on this lush midsummer evening. But few of the impeccably groomed diners in this painstakingly casual and clearly affluent crowd—Ralph Lauren’s polo player is galloping across half the chests in the room—are paying much attention to the magnificent natural setting.
    It’s the opening night of the season at the chicest restaurant in Cap Ferret, one of the chicest resorts in France. Just an hour from Bordeaux, the town lies at the tip of the long, thin peninsula of dunes and forest that forms the western arm of the Bassin d’Arcachon, France’s beautiful and rather secret “South Sea.” And though no one would admit it, there are people in the crowd who called days earlier from halfway around the world to make sure that they’d get a table on this most strategic of terraces. The inevitable denials of the natives notwithstanding, this is the night to see and be seen in a place where appearances count for a great deal.
    To grasp “Ferret,” as the locals affectionately call it, imagine a Gallic version of East Hampton, then add the perfect social graces and restrained elegance of the Bordeaux bourgeoisie and a sprinkling of aristocrats. Along with, bien sûr, the occasional scrupulously ignored celebrity—Bordeaux mayor Alain Juppé, Johnny Hallyday, Léon Zitrone, Jean-Paul Belmondo—adding a bit of glamour to the crowd.
    What you won’t find here, in large numbers anyway, are foreigners, and that is one of the things that makes this corner of France, the world’s most visited country, so alluring. It’s not that Cap Ferret is xenophobic, it isn’t, but rather like several of the world’s other exclusive summer communities—the German North Sea island of Sylt, or the gated pine glade of Point O’Woods on New York’s Fire Island, a favorite with New York Times staffers—there’s a very limited number of hotel rooms available, most of which are booked far in advance, so you either own your own digs or are forced into the dreaded category of day-tripper. And although Dutch and German campers may like to be near the ocean beaches, almost everyone else in this franchouillard, or super-French, station balnéaire is happier dallying on the Bassin d’Arcachon itself. Never mind that the residents of Pyla, the area’s other furiously chic resort town at the entrance to the bay, make a firm point of their preference for the “pristine” (you get the implications insofar as the Bassin is concerned) Atlantic waters.
    Pyla, with its large “Basco-Landaise” villas (half-timbered whitewashed houses with long, low rooflines built by three generations of the Gaume family), likes to imply that it’s more “discreet” than Cap Ferret. And it’s true that the great families of France—the Rothschilds, Debrés, Mauboussins, Taittingers and Bettencourts—come here to escape the public eye. The only place you might catch a glimpse of the local gratin is over dinner at La Côte du Sud during the summer; out of season at La Cabane, where they grill meat on an open fire; or at Les Deux Chênes, known for its cèpes. Aside from these restaurants, though, there’s little way for an outsider to experience the posh local life.
    Pyla and Cap Ferret may be the Bassin’s twin compass points of exclusivity, sharing a sort of anti-Côte d’Azur philosophy, but they tell only a small part of this lovely bay’s story. This vast tidal basin—more than three-quarters (about 62,000 acres) of which is exposed at low tide—has been attracting vacationers since at least the fourth century, which is as far back as archaeologists have been able to date the Gallo-Roman ruins in Andernos-les-Bains, a large and well-established resort and oyster-producing town on the eastern flank of the lagoon. Here, the powerfully simple Romanesque church of Saint-Eloi sits on the shallow banks of the Bassin, and excavations have proven that the Romans had established a sort of rough-and-ready spa here using the salt- and mineral-rich mud to treat rheumatism and other maladies.
    Odds are that the Roman curistes scarfed down an oyster or 12 as well, considering that the Bassin’s most ancient vocation is oyster fishing. Originally, the bivalves grew more or less wild here, but then in 1852 Vincent Coste, a local fisherman, designed the first oyster-seed collectors. Jean Michelet, another waterman, later developed the liming technique, painting concave tiles with lime and stacking them in the sea, making it easier to later detach the oysters that would cling to them.

Photos: Jean-François Jaussaud; ©SCOPE/Jacques Guillard