There in the front row of Valentino's latest show were the wealthy and fashionable ladies of Paris: Paloma Picasso, Suni Agnelli, Marie Helene dexl Rothschild, Olympia de Rothschild, Doris Brynner.

Jessica Lange wore a Valentino to this year's Academy Awards, and accepted her 1983 Oscar in one. Nancy Reagan bought Valentinos in California before she became first lady, and invited the designer to the White House for a private visit on his last trip here. Jacqueline Onassis is a good friend and regular client -- Valentino created the wedding dress for her marriage to Aristotle Onassis.

And Washington isn't without fans: Princess Haifa, Louisa Biddle Duemling and Mary Jane Wick are among the most faithful. "It's hard to think of a friend of mine who hasn't bought a Valentino," says Val Cook, consultant to Saks Jandel.

A designer of great taste, Valentino Garavani (no one uses his last name) makes clothes that are clean, modern and worth their high ticket price. "You spend $1,200 for a Valentino suit and the workmanship is like couture. Just look at the buttonholes and buttons -- it is the first giveaway of a good tailor," says Rose Wells, e'minence grise of fashion retailing. "Owning a Valentino is like owning a Madame Gre s tucked jersey dress -- once you've bought it, baby, you don't want to give it up. Women who own his clothes wear them for years and years."

His influence is subtle -- no shocks -- but strong. He was the first to inset lace in the backs of sweaters, the first to show sweaters for evening or paired with silk skirts and wool jackets. His chain print was copied years ago, and his new animal prints will also have followers. And when his important detail was button trims, not only did he sell thousands of styles trimmed this way but others did, too.

Quietly and steadily over the past 25 years, Valentino has built one of the most successful high-fashion enterprises in the world. He has become the mass marketer to the rich, the mastermind of a $250 million business at wholesale, more than half a billion dollars at retail. Last season he sold 6,000 of his zip-front, button-trimmed $1,000 sweaters, and last year he sold 300,000 dresses in his Miss V line, at an average price of $800. He has 16,000 people on his payroll.

It all makes him nervous, he says. But there is hardly a endcol gray hair to show for it.

Slim and tan at 53, Valentino unbuttoned his impeccable double-breasted jacket and stretched an arm across the back of a sofa at the Watergate Hotel. He was in town recently to see his newly renovated boutique, and to talk about his favorite subjects, beautiful women and beautiful clothes.

The two work together, and one must never forfeit femininity for fashion -- "that's a ground rule," he says. "Femininity is good material, not too stiff, and a cut, not too masculine. When you have good shoulders and beautiful hips the dress is always feminine and a big success."

Sexy is another matter, "the movement of the women in the clothes . . . And the dress, to be sexy, it has to move around the body in a soft way, not being vulgar. The de'collete' in different ways is sexy, but not anymore the slits. It's overdone, and I've done it a long time ago, and now it's too easy and not very elegant."

Sexy does not mean tight, but rather sinuous. "Tight is vulgar," he says. And sexy doesn't necessarily mean short. "For the moment I prefer to make short clothes. I make a little longer for winter time."

Valentino disregards the big fashion swings, such as the oversized styles first shown by Japanese designers. "Women love to be slim," he says. "To be camouflaged means shyness -- not personality, rather insecurity. So to be slim and showing the forms and the movement of the body, it means security and intelligent human being. If you are slim, you are more comfortable, you please more people around you and you feel better about yourself. You move better. And you have this sort of natural way to move that is a part of elegance."

He adds, "I prefer too thin to too fat." His mannequins are very small and, in fact, quite flat. "I use very slim models without bosoms to be free to create. Sometimes, if the model has a bosom or a little big hips, it gets in the way. That is important when I create something new. Later it can be translated for women much larger."

He keeps himself slim with an exercise regimen that is practical, if not very organized. "I always put my weight stuff at night in the middle of the bathroom. Then when I wake up in the morning I have no choice but to pick it up." He doesn't feel comfortable if he is not constantly moving. Passionate about skiing, he spends three or four hours a day on the slopes while on holiday in Gstaad, Switzerland. "I started skiing four years ago and, you know, they say that I am good," he says with a boyish chuckle.

The skiing helps his perpetual tan, but he admits to boosting it with the help of "a little lamp, I must tell you. I went to New York and twice did 20 minutes of a lamp, I must confess."

He adjusts his jacket, twists his Pasha wristwatch and begins to talk with the same honesty about his beginnings as a designer.

"I started designing when I was 12 and 13," he says. "Drawing, drawing, drawing, without any proportion and without any sense. I was very good designing in freestyle, as they say in Italy, so I was a disaster at geometric style. But I could do shoes, blouse, scarf, skirt -- I did everything. All on top of my schoolbook."

His mother was not overly interested in clothes. "She was a provincial woman, never badly dressed," he recalls. "I remember in Voghera, that provincial city near Milan where we used to live, there were two sisters who were dressmakers, and they were extremely good and very expensive for the time. And I remember my mother going there, without the permission of my father, and having three things, not very much, but three things perfect, of good material, made. So I've always seen my mother well dressed."

His parents hoped he'd become a doctor, but "I did not want to be a doctor. My studies were very peculiar. I was very good in Italian, my mother language, and in history and geography. I was a disaster in mathematics, a disaster in philosophy, Greek and Latin, mainly because I couldn't care less. I couldn't pay attention, because in my head I was a big dreamer."

When he told his parents he wanted to design clothes, they were shocked. "Extremely shocked," he says, "but they were so fantastic. You can imagine, it was 1950, a time not like now. To want to stop your studies because you want to go to Paris? Mentioning Paris in a provincial Italian city in the '50s was like mentioning China. A boy of 17 years!" Reluctantly, they agreed.

They knew a pattern maker in Milan who had an apartment and worked as well in Paris, and they rented a room from her for Valentino. "She saw in me the chance in her life to pay everything in the house," he says. "She was somebody who was very direct, without shyness."

After six months in the school of the Chambre Syndicale, Valentino went to work in the studio of Jean Desse's. He was one of three assistants, and very often in the studio with the designer when he was preparing his collections. "From Jean Desse's I learned chiffon," he says.

Six years later he moved to an assistant's position at Guy Laroche, the former first assistant to Desse's who had just opened his own house. During his two years at Laroche, Valentino did everything. "I even went with the photographer on the set to prepare the girl for the pictures. I was helping to dress the girls for the show. I was sketching thousands of things for the collection, because sometimes he was away. I did so many things on my own because we were a small fashion house, and I learned a lot."

In 1960, at age 28, he asked his father, who had an electrical business, to help him finance his own fashion house in Rome. Italian fashion had begun to come into its own while Valentino was working in Paris. "Before that, Italian fashion was mostly dressmakers copying the French line. By 1960 Fabiani and Simonetta, Roberto Capucci and others had just started up."

In the beginning there were many "little mistakes and not much good help. But always there were customers." Sophia Loren was among his early clients. And while other designers made drastic changes in their collections for each season, Valentino stuck to his formula for pretty, feminine clothes. "I was criticized at first, but in the end they knew I was right."

His first American success was in 1965 in the basement of Bloomingdale's, a coup hailed in the fashion pages of all the New York papers. Hana Mackler, then merchandise manager of the basement, had paid $1,000 each for Valentino's toiles, or canvas patterns, and had the clothes made in New York using Italian fabrics. They were mostly coats, semifitted and short, she recalls, in tweedy wools -- and they were a sellout at $70 retail.

"I knew his reputation and found him working in Rome in a palazzo on the via Gregoriana, not far from the Spanish Steps," says Mackler, now president of an import shoe firm. "He was very handsome, very young, but not as sunburned as today," she laughs.

Valentino made an appearance at Bloomingdale's storewide Italian promotion, even though he wasn't well known enough for the store to pay his way over. Mackler wanted to do a similar promotion with him the following year, but by then he was selling his toiles for 10 times as much. "I just lucked out. I caught him the season before he exploded," Mackler says. "The following year all the better stores wanted him. His toile prices had jumped from $1,000 to $10,000 in a year. I couldn't afford him anymore."

The next year it was the posh Park Avenue shop Martha's that showed his designs -- and introduced Valentino red, still a part of every collection. It was a far cry from Bloomies' basement, and it hasn't let up since.

In 1970 Valentino decided to make more affordable clothes and moved into pre't-a'-porter, first with the prestige French house Mendes. Today his ready-to-wear line is manufactured by GFT in Turin, which makes the clothes of Emanuel Ungaro, Giorgio Armani and others. "There is not anymore a center of fashion -- Paris, Italy are exactly the same," he says. "There is maybe a little more fantasy in France. They are concerned with a complete collection. In Italy they are more concerned with a good sport look."

He shows his couture collection in Rome, his ready-to-wear in Paris. "It was my choice at the beginning not to show with the French designers," he says of his decision to present his first ready-to-wear line in a restaurant in the Bois de Boulogne rather than in the tents in the Tuileries used by the French designers. "French people love themselves very, very much," he adds. "It takes a long time for French people to accept somebody from the outside."

Along with his ready-to-wear -- always spun off from the couture collection, which is the basis of his huge business -- there are also Valentino linens and gifts for the home, and a new product, Valentino perfume. "I told the technician to mix strawberries and white camelia, for instance. It's an idea, and after they try it, it seems to work."

His first attempt at a fragrance, in 1978, didn't. A mix of tuberose and melon, it was launched in Paris at a performance of Tchaikovsky's "The Queen of Spades." But even Mikhail Baryshnikov's dancing couldn't get the perfume off the ground, and it failed a few years later. Valentino's business disappointments, however, have been few.

A year ago he came out with jeans, and now sells 1 million pairs annually. They are "normal jeans of very good denim material," made in Italy. The "Made in Italy" is important to him. "I need to have control. I need to see my fittings. And what do you do if it is not right and you are manufacturing in Hong Kong?" So many young people want his jeans he cannot sell them in his own boutiques -- the stores are too small to handle the crowds.

His menswear line, Valentino Uomo, "is established. You expect elegance, good proportion, a masculine way to be dressed. There may be a slim jacket or one a little boxy, lapels a little smaller or bigger, but a man has to be always dressed like a man. When we -- I speak plural for all of us -- start, we do sometimes a little detail too much. That's not for an extremely elegant man, rather for a small group of men who are too much in vogue and fashion, and so to me they are not elegant."

When he was younger he dressed in fitted open-neck shirts and gold chains, but in recent years he always appears in classically tailored double-breasted suits or single-breasted sports jackets and near classic shirts and ties. "When we show the men's collection I am very happy when I see the boys go out in gray flannel suits with beautiful shirts and beautiful ties." An elegant man, he says, always wears a light blue shirt.

Valentino is confident when he talks about style, but he defers to Giancarlo Giammetti, his friend and partner, when asked business questions. The figures are huge. "I think, including men's and women's things, last year we made more than 1 million things for sale," Giammetti says.

It is not all work for Valentino, but nearly so. He can relax at his houses in Capri Italy , Gstaad, and Rome, and when in Paris he stays at the Plaza Athe'ne'e, across from his boutique on the Avenue Montaigne. "I would love to have an apartment in Paris," he says, "but time is so tight. You have to enjoy houses, and already I have to fight with myself, with my work, to go around and stay in my houses. You can imagine if I had another one. It's impossible."

At the moment he's fighting to restore serenity to his work place as well. A McDonald's, recently opened in Rome's Piazza di Spagna, backs onto Valentino's atelier. This week he asked magistrates to order its closure on the grounds of nuisance, complaining that the fast food restaurant creates "significant and constant noise and an unbearable smell of fried food fouling the air."

His apartments are for entertaining friends quietly, but he's well known for his splashy parties. One Arabian Nights extravaganza, coinciding with a Near Eastern-inspired evening collection, took place under a specially built tent at the Hotel Pierre. Another, a lavish dinner, celebrated a collection shown on the stairs inside the Metropolitan Museum of Art. At Jackie O, a night club in Rome, Valentino threw himself a birthday party at which all the jet setters dressed in black and white and a starlet popped out of the cake.

He is now looking forward to the debut of his new perfume next year. "But people are bored with parties," he says. "I don't know what it will be. But we'll try to do something elegant and special."

You can count on that.