FRANCE, we were told, was sinking into the Atlantic from the weight of all the Americans this summer.

In Normandy, hotels (and even farmhouses with freshly painted "rooms to let" signs hanging from their gates) bulged with tourists taking advantage of the "heavy" dollar and commemorating the 40th anniversary of the Allied invasion that turned the tide in World War II. But in the south, in the hills overlooking the Co te d'Azur, another important anniversary was noted, with another American "invasion" at its center. It was the 20th summer for the Fondation Maeght, that extraordinary art museum and sculpture garden near St. Paul de Vence, one of the world's most significant showplaces for modern art.

Twenty years ago, art dealer and publisher Aime' Maeght, weeping over the death of a son, sat beside a stone wall of his own hillside villa with his friend Georges Braque. It was Braque who suggested the memorial: a living, exciting environment to show monumental 20th-century art, indoors and outdoors. "Something really big," Braque said, and pitched in. So did Le'ger. Giacometti. Henry Moore. Miro'. Chagall.

The permanent collection, which continues to grow, is peopled with other contemporary giants. Arp. Bonnard. Kandinsky. Matisse. And the Americans Ellsworth Kelly and Sam Francis. In the quietly dramatic gardens, huge sculptures seem as natural as trees. Inside, major exhibitions are mounted every summer -- a lifetime of Klee, a world of Miro'.

The Maeght's director, Jean-Louis Prat, has assembled each of the 20 breathtaking summer showings. One I particularly remember was the collection of Joan Miro' four years ago, with the tiny artist, then 84, bobbing around in the garden in the shadows of his giant "puppets." "There is nothing quite like the Maeght in all the world," Miro' said.

For this year's 20th anniversary, two living artists, in separate one-man exhibitions, represented the art of our century: Russian-born Marc Chagall, at 97 a French citizen and still painting, and 58-year-old Robert Rauschenberg of Captiva, Fla., and New York, a native of Port Arthur, Tex.

This summer, I spent a day with Prat to ask "Why Rauschenberg?" Why is this rangy, globe-trotting, passionately liberal, antiwar former sailor now considered one of the world's giants?

Prat, a slender, trilingual sophisticate with worldly-wise crinkles around his blue eyes, has just returned from a Paris meeting with Chagall. Next he's off to Moscow to straighten out something about a state-owned painting he needed. A museum director is always balanced precariously, he said. "But the art. Ah, to see the art. To show the art. To watch the people respond. It is worth it. This is the most exciting life I could imagine."

We had just turned up the adjoining hillside to the Mas d'Artigny, a splendid resort hotel whose restaurant shines with a Michelin star. From the poolside terrace, we looked across a valley yellow with the fragrant broom that also bloomed on Impressionist canvases, over at the ancient stone walls of St. Paul de Vence, where young Matisse, Dufy, Le'ger, Rouault and Picasso left their paintings for room and board. Down the hill, we could see the Mediterranean, as blue as the sky, dotted with sailboats. Art was in the air, in the sea, in the hills, as Prat tried to explain to me why Rauschenberg, this once-maverick American, was drawing such crowds in the cradle of so much important European art.

"Rauschenberg, for us, represents his portion of the 20th century, especially the 1960s, the years of our beginnings," said Prat. "Through his 'complex order due to chance,' he has brought us not only the moments -- the times in which he lives -- but he has transformed the sensibility of those moments into the permanence of art.

"The 1960s, our anniversary years, were very important for America in Europe," he continued. "It is really important for us to see the vitality of American artists and to understand that they saw -- and still are seeing -- new possibilities in painting . . . The new American painting burst forth with a special energy, an e'lan, an inventiveness, and a constant renewal. The effect of this art on the world of the 20th century must be looked at. It is important that we capture this new sensibility.

"The Americans have reflected our society. As we live in a society where everything moves so fast, they the American artists understood that it was not necessary to speak of the past, but of the moment.

"Rauschenberg . . . Jasper Johns . . . Sam Francis . . . and, of course, Pollock, Kline, Rothko, etc. . . . these are the important artists of our generation, just as Miro', Chagall, Matisse, Le'ger and Picasso were to their generation. The Americans brought to the rest of the world, in the language of art, absolutely what was America. They understood that to make new space, new materials, a new view, was to take a new breath in art.

"The European heritage of art is, of course, ancient and irreplaceable. But now, the Americans have a short heritage of their own -- and we see it as a movement, one that has continuity and renewal. And this movement, this heritage of yours, has come to influence the world of art.

"So Rauschenberg is now an 'Old Master.' We look back at his work -- and it is necessary to study him -- because he understands the language of this century. So when I see a painting of Rauschenberg's it's not a 'new' painting. For me it is the language of this century."

In those hills, under that sky, I suddenly felt that France was not sinking, but rather about to float upward, somewhere near where I was at the moment, buoyed by the weight of the Americans.