Forget April, It’s August in Paris : AMBITION AND LOVE, <i> By Ward Just (Houghton Mifflin: $22.95; 288 pp.)</i>

August in Paris is the month of the Americans. The avenues are wide open, the parks are full of shaded romantic corners, and while most of the French have followed each other to the sea like lemmings, just enough remain to keep open the critical mass of cafes. Americans love this season because without the hard-to-take Parisians, the city is so easy, “so lush and accessible, so graceful and finished, loaded with lore,” as the narrator of Ward Just’s new novel tells us. And if I were going to Paris just now and wanted a feel for the place and for the particularity of the American experience there, I would take this book with me this summer.

To be sure, “Ambition and Love” has about it an air of anachronism, but its subjects make that inevitable. It tells the story of an American writer--a man--and an American painter--a woman--who knew each other a little bit in Chicago and didn’t fall in love, and don’t fall in love again, but who shared a certain dream of what their lives could be if they devoted themselves to their art--and who believed that Paris would be the place to do that.

As long as there have been Americans abroad, from Thomas Jefferson to Jimi Hendrix, Paris has given them a mixture of inspiration and indifference that caused them to thrive, then let them. But for writers and painters, the 1920s were the great moment, and in the popular mind of America, the city has remained frozen like a wax museum filled with figures from les annees folles . The peculiar excitement experienced by American provincials faced with cosmopolitan grandeur and the glorious hedonism that followed World War I is not to be repeated. But the shades of Hemingway and Fitzgerald and the Murphys linger on, and authors flock to Paris now not so much for inspiration as in emulation.

The writer in this book, Harry Forrest, has settled for the good life along the banks of the Seine, browsing the bookstalls to check the prices put on used copies of his mystery novels. Those too are about the city. District by district. “Inspector Pease and the First Arrondissement,” “ . . . and the Second Arrondissement,” and so on, spiraling along the historical nautilus of the metropolitan map from fashionable houseboats along the Seine near Notre Dame to the dreary immigrant-filled streets of the 10th, which is where his wife decides to leave him, sick of doing his research, and tired of deracination.

He would have us believe that after 20 years she had become too snob , too BCBG ( bon chic, bon genre : preppy, bourgeois). But it’s she who goes back to the States. Harry has become too comfortable in the American niche. “La Belle France--so supple on the surface, and so glacial underneath,” an old expatriate journalist tells him. “You will admire the bedrock. You will approve of it--because you’ve never stubbed your toe on it. Let me tell you, Harry. It hurts like hell. But because you’re an absentee American, you’re excused. This is a fact you will come to appreciate, and cling to for dear life.”

Not so Georgia Whyte, the painter, who knew Harry when she was a beautiful young girl from the less respectable side of the tracks and his brother brought her to a country club dance in Winnetka. In middle age she has become that other kind of American who comes to create in Paris: one who has little familiarity with the language or interest in the culture or desire to learn. “I have elected to live as a fugitive among strangers, remote from the life of my own nation, unconnected to the life of this one,” she writes to her relatives. Yet she blends in very quickly.

They have not seen each other for decades when he runs into her at the Musee D’Orsay, which is one setting earlier writers could not have exploited. It used to be a train station. But since the late 1980s, with its chaotic open spaces filled by non-threatening art from the 19th Century, it suits the mood especially well of foreigners who want at once to lose themselves in the city and to be in a place that they know. When they meet, both Harry and Georgia are eyeing the genre painter Couture’s enormous canvas “ Les Romains de la Decadence ,” which oddly prefigured the life if not the art of les annees folles . The disapproving bust of Caesar glowering over the Roman orgy “bears a passing resemblance to the Ohio Republican Warren G. Harding,” Forrest informs us. But now the painting just looks like campy romanticism. Decadence is so much easier to enjoy than to capture.

Over carafes of wine in a nearby brasserie, Georgia tells Harry her story, and he tells us. It’s a tale of ambition and, if not love, then lovers; a simple narrative but a complicated problem as she moves from Chicago to L.A., from the man of her life to a menage a trois, then to Paris and solitary confinement with her canvas. She sacrifices long relationships and the possibilities of quick success in order to keep painting exactly what she wants to paint. And in the end, she produces work that satisfies her and disturbs others, and she is found by a man who marries her, and she has a beautiful child and gets the hell out of Paris (if only to the rural delights of remote Auvergne). She satisfies her ambition. She gets love. While Harry is left with no wife and no work he can really be proud of. “Her life was triumphant,” he concludes.

Sure. It’s a fairy tale. But that’s what Paris is about for those who come to it from America; the Oz where a woodman gets a heart and the scarecrow a brain, and the would-be artist gets respect. The death of Harry’s friend, the old expatriate journalist, “was mourned in every arrondissement. His memorial service filled Saint Philippe du Roule.” When an immigrant songwriter dies, the streets are overflowing with distraught fans. “You cannot know what it is to be mourned by a city,” Georgia dreams afterward, “to have your work so revered that the public weeps, comes with flowers to the front door of your house, feels your death as it feels the death of a beloved member of the family, remembers your most casual and thoughtless remarks as emblems of a whole nation, is drawn to you as iron to a magnet, sees you in their dreams, adores you, would raise you from the dead if they could.”

Paris was ever, and remains, a place where a man or woman from America could invent themselves as artists, even if they were not very good ones, and could dare to think they’ll be loved. For most, that is ambition enough.