Maybe it's the French accent, thick as onion soup, or the Rabelaisian beard and long hair, but somehow Sam Lopata is charming even when he's throwing a fit.

"This is tayrr-ee-booll!" he's shouting. "It's a dee-zass-tayrr!"

Lopata is staring at a square opening that has been cut into a wall of a restaurant under construction on Manhattan's East Side. He had designed the restaurant, which will look like an old mining town and be named Home on the Range, but he hadn't called for any such hole.

One of the owners explains with a touch of wounded pride that the hole will make it easier for his busboys to return dirty dishes to the kitchen.

Lopata values efficiency, but he values a seamlessly sustained mood even more. In the design business there is a saying: "Everything is a message," meaning, there is no such thing as a minor detail. "You can see zees hole from the dining rroomuh!" Lopata protests. "You want your cus-toe-mairrz to see a guy hosing ze dishes?"

The owner looks skeptical. "No, no, I'm sayrr-ee-uus!" Lopata warns, wagging a finger. "Don't do eet!"

The owner huddles with his partner. Lopata may be a teddy bear, but he is not to be toyed with. In Manhattan, where new dining spots vie fanatically for the patronage of an increasingly fickle public, a designer's record may count for as much as the chef's, and in the past decade Lopata has helped create 23 restaurants and nightclubs in Manhattan alone. Many have been controversial, many acclaimed. Virtually all have attracted clamoring crowds. "Sam pioneered the concept of restaurants as social showcases," says New York Times restaurant critic Bryan Miller. "He has many imitators, but he's an original."

At Home on the Range, the partners concede. The hole, they announce, will be sealed.

Was Lopata really as angry as he seemed? His eyes widen comically and his head jerks back like a startled chicken. "I said it nicely for two weeks, but nobody listened!" he exclaims.

Lopata's strongest emotions are often leavened with humor. When he blows his stack, says his longtime girlfriend, Gayle Osman, "it's as if a leprechaun is doing it." Which is fortunate, because, as Lopata proclaims with a whoop of isn't-it-absurd? laughter, "I fight with everybody!"

He fights, for example, about carpeting, which he loathes. Restaurant owners like carpeting because it feels good underfoot and keeps the noise level down. Lopata doesn't mind noise. "Noise brings life," he maintains. "What bothers me is an un-noisy space, like a hotel lobby. Something is wrong with that."

Lopata sees himself as guardian of the diner's freedom and dignity. "It bothers me when I arrive in a restaurant and right there by the door somebody grabs me and says, 'Who are you and what do you want?' " he says, grabbing an imaginary patron by the lapels. "Me, I like to wander around, feel the room, then I can ask about my reservations. So when I design, I put the maître d's station farther back. And do you know what they do?" His eyebrows leap.

"They move it back to the front!"

In the most competitive restaurant city in the world, three designers stand above the rest. Phillip George, 64, who designed the new Rockefeller Center restaurants, has been at it longer and represents, according to noted restaurateur and author George Lang, "the top of the heap in an American way of thinking." Adam Tihany, 39, is a rising star who brings Italian style to what Lang calls "a contemporary representation of the past." Lopata, 46, is more eclectic than either of them. Born and raised in Paris, he has translated the Parisian brasserie and the French country restaurant into hip New York terms. He prides himself on never repeating a concept. His trademark, however, is puckishness.

"There are a lot better designers than me, for pure design," he says. "I create environments with some controversy. Environments with a smile."

The smiles include EXTRA! EXTRA!, in the New York Daily News Building, a cacophony of magnified headlines, cartoon characters and "spilled" red printer's ink on the floor; Pig Heaven, an all-pork Chinese restaurant done in whitewashed barn siding with pink lights blinking behind a frieze of wooden pigs rooting in the grass; and Lox Around the Clock, a 24-hour deli whose interior Lopata left stripped bare, creating what has been called the "demolition look."

"If Sam didn't exist, he would have to be invented," Lang says. "He's a nose-thumber, a child in the best sense. He knows how to satisfy the fun-loving hedonists of our time."

Yet Lopata is also the designer who last year gently refreshed the look of Lutèce, perhaps the best French restaurant in America, and who is about to do the same for the Broadway institution Sardi's. It was he who created Prunelle, a jewel box of burled maple and mirrored floral displays that New York magazine critic Gael Greene calls "one of the most beautiful restaurants in New York." He knows when a joke would not be appropriate.

"Before I design concepts or anything," Lopata says, "I mold the space. I lay the thing out—where the kitchen and bar will be, how the traffic will flow.

"It's like creating a body," he explains. "If you are well-built, you can wear any clothes, and they always look good. But if," he adds, beginning to laugh, "you are a little crooked or whatever, you can buy Armani or anything you want and it will never work. So I work on the body."

In recent years, Lopata says, Americans have become so sophisticated about food that "the dee-fairr-ontz between here and Europe is now vai-rry narrow." But he decries what he considers false sophistication. "When the waiter opens a $10 bottle of wine for you and gives you the cork to smell, it's bull——! The cork on a $10 bottle of wine doesn't smell like anything. Just put the bottle on the table and let people serve themselves."

Lopata also has it in for the now-ubiquitous dessert cart ("You've got the chocolate mocha cake, the chocolate mocha mousse cake, the Belgian chocolate truffle tart...one is enough!") as well as status-conscious waiters who will "never admit they're waiters, even though they make more as waiters than at their 'real' jobs."

When Lopata and Osman eat out, they go to mom-and-pop joints, ethnic places where "design" means that the napkins might match the tablecloths. "A relaxed environment, everybody talking to each other like a big family, that's what a restaurant should be," he says. "I have been raised like that."

Lopata comes from a family of prosperous Polish bakers. His father, Salomon, moved from Warsaw to Paris in 1925, and five years later sent for his old-country sweetheart, Eva, a hatmaker. Together they opened a hat factory. "My mother was very pretty, and my father was very tall and elegant," Lopata says. "He was a big gambler. He loved life. When the Nazis occupied Paris, he never believed anything would happen to him, because he was very friendly with the police."

But the Gestapo arrested Lopata's father in September 1941 during a raid on a bistro. With other Jews, he was held for 10 months in a warehouse outside Paris. The best the gendarmes could do was warn his pregnant wife, also Jewish, not to return to the apartment. With the aid of the concierge, she moved into the building's attic with her two daughters. Three months later Sam was born. Before Sam's father was sent to Auschwitz, where he died, he received and joyfully answered a letter confirming the birth of his son.

The surviving Lopatas lived with families in Normandy for the rest of the war. Returning to Paris afterward, they were destitute. "We had nothing," says Sam. "My mother sewed hats at night, and at 5 a.m. she used to put them in a little cart and go to flea markets. Some days she sold two, three hats. Some days she didn't sell any."

Sam's mother never remarried, and his older sisters went to work to pay for his education. "[At home] I could do no wrong," he says. "Maybe I took advantage, but my attitude was always to live right now, because yesterday was so bad and tomorrow didn't look too good either."

Though Lopata never knew his father, he grew up much like him—gregarious and lighthearted. Not having a father never troubled Lopata ("The street was my father," he remarks). He says he has "never wanted to know" the details of his father's arrest and deportation. So it is intriguing that Lopata has made a career of inventing over and over, in different forms, the kind of place where his father disappeared. For Lopata this is the scene of the crime, and in a sense he has never left it. Of course he becomes infuriated at the thought of anyone accosting patrons and asking, in essence, "Who are you and what do you want?" For him a restaurant is a refuge too easily violated. Putting in the smile keeps his father's memory alive.

If bistros were classrooms, Lopata could have boasted of perfect attendance. But when Lopata flunked his university exam finals, his mother and sisters decided his future lay in banking. It was like a prison sentence, and Lopata made his escape from clerking as soon as he could. Eventually he enrolled in architecture school, largely because a friend told him that student architects organized a lot of parades and public festivities.

An indifferent architect, Lopata was more inspired as a prankster. He and his friends once brought a gift-wrapped box of 10,000 marbles to the wedding of a fellow student. The box had a trick bottom, and when Lopata handed it to the poor fellow, 10,000 marbles rained down on the polished dance floor. "Waiters were sliding, kids were stuffing marbles in their pockets," Lopata says. "The place emptied in less than 20 minutes."

Lopata came to New York in 1971 and soon afterward met Osman, a vivacious young woman from Brooklyn who worked as a sales representative for Halston. She thought him "outlandish" but adorable in his velvet coveralls and dramatic capes. Two months later they decided to try living together for six months. The clock has been running for 15 years, unwatched.

For a while Lopata designed wall units and waited on tables at a restaurant owned by his countryman Robert Pascal. In 1976 Pascal decided to open a new place and offered Lopata $2,000 to design it. At Chez Pascal, Lopata set blond wood and bare brick beneath an unpainted tin ceiling, a novel combination at the time. But it was the quilted gray ultrasuede banquettes—Gayle's suggestion—that got people talking. A second project led to a third. Before long, says Lopata, "people were calling me a designer."

Some also call him expensive. "Sam's very entertaining—he made me laugh—but he doesn't believe in doing a job for less if he can do it for more," says the owner of one of Lopata's latest creations. Yet it's not a question of personal gain; Lopata is a perfectionist who wants artistic control. As a token of good faith, he sets his fee at 8 to 15 percent of the initial construction budget, which usually ranges from $500,000 to $1.5 million. If the budget goes up later, his fee does not. "I don't know any designers who get rich doing design," he says. "If so, they're not doing it honestly."

To save money, one owner wanted to use a conventional, off-the-rack light fixture instead of having Lopata design one. Lopata searched, and finally found one. It was just a little too long, he decided, but it could be cut down. Then, after it was cut, he decided it was too short. Improvising, he designed a polished copper cylinder to lengthen the base of the fixture. "By the time he was done, it cost me as much as a custom light," says the owner, while conceding that the idea was effective.

To Lopata it's still a dee-zass-tayrr. Not only does the owner set light levels too low in his restaurant, he says, the man also refuses to pay for a computer that would set them automatically. That is, it would set them automatically the way Lopata would like. Lopata is fond of computers for just that reason: They are quiet, they are obedient, and they never put holes in the wall where they shouldn't be. If he could say the same for all of his clients, he would be a vai-rry happy man, but just a bit bored.