Yves Saint Laurent once called the Vicomtesse de Ribes "the pearl in the King of Poland's ear, the Queen of Sheba's tallow-drop emerald . . . She is a castle in Bavaria, a tall black swan, a royal blue orchid, an ivory unicorn . . . She is the quivering aigrette topping a maharajah's turban in whimsical and baroque spiral."

To almost everyone else, Jacqueline de Ribes is simply the epitome of elegance, her eminence of chic. Her fashion sense is unfaltering -- since she was 20 years old she has topped every best-dressed list.

Last Saturday morning in her small suite at the Four Seasons Hotel, just arrived from California on four hours' sleep, she was the essence of elegance. Wearing pencil-slim jeans, a plaid shirt and white cashmere sweater, she perched on a love seat, one leg tucked under her lithe, lean body like an exotic African bird.

She had been on the road for more than two weeks, promoting her line of clothes in California, and had come to Washington to meet with customers at Saks Fifth Avenue and to make sure that every detail of fit and design was in order at her fashion show to benefit the National Theatre.

She could, of course, be back in Paris, where she lives in an antique-filled town house on the Rue de la Bienfasance with her international banker husband, and where she is admired as a mother, grandmother, international hostess, television producer (with Liza Minnelli's first French TV special to her credit) and energetic charity organizer.

But more than a year ago she removed all but the wall-sized tapestries from three rooms of her house and presented her first collection. Saint Laurent, Valentino and Emanuel Ungaro, designers she patronized, were in the front row applauding. Now her clothing designs -- which can cost up to $5,000 -- and her jewelry are a huge success in this country and will soon be sold in England, Germany, Italy and Switzerland.

Many were skeptical when she started. "Not my family and people who know me and are close to me," she says. "Nobody in the world of fashion. Not my fitters in the maison de couture. For so many years I have said, 'Wait and see, one day I will go off on my own.' Then one day I said, 'My God, they can't be waiting that long, and I can't be waiting that long either.' "

She had designed jewelry, designed her own clothes, designed clothes for her family, her sister and mother, but had never created her own line -- "for lack of courage," she says. "Finally, I just said, 'What is lacking here that makes me so unhappy is courage, self-confidence.' " Her friends and family supported her. "It piled up in my head, and finally I picked up my courage to do it."

There have been no regrets, "not even surprises," she says. "I'm just learning. I knew it was going to be total dedication, but I didn't realize that it was going to shut me off from sharing the holidays with my husband and not seeing my children, and this it does. There is no resentment in the family, only they hope it will change, that the pace will be different after three and four years. Maybe I won't have to do the tours."

Then she adds quietly, "A choice is a choice. In France we have a saying . . . choosing is in some way dying. It is true. If you choose something, you are certainly dying off other possibilities in your life. You choose something, and you know what choosing means. If you start regretting, and saying, 'Maybe I should have done this and this,' then you get neurotic and you have to go to the doctor." She stops and smiles. "I haven't had to go to the doctor . . . and I am not going to."

Although designing is a new profession, it has always been a part of Jacqueline de Ribes' life. She would dress up in towels or whatever else was handy as a child. She was not encouraged to take an interest in clothes by her mother, the Comtesse de Beaumont, a writer who translated all of Tennessee Williams into French. But when the couturiers would come to fit her grandmother, she would sneak into the room and watch them work. "I have always been fascinated by the techniques of the thing. From the first day I saw a fitting had to know everything about how it worked," she says.

She had very strong ideas about fashion, even at age 6. "I wrote a letter to Father Christmas giving him my measures and the description of the skating dress nobody wanted to give me." She remembers it well. "It had to be royal blue velvet trimmed with white fur at the cuffs and hem, and I wanted a little fur hat to match. I took my measures in front of a mirror with a tape. And I was very disappointed that I never got my dress."

In boarding school she always designed the sets and costumes for the school plays. And at age 16 she cut out her first dress on the living room floor -- a dress to impress her fiance', the Vicomte de Ribes, whom she married the next year. Her husband Edouard, now a comte, was 24, and she was "such a baby" at her marriage, she recalls now, "my wedding gown was like a communion dress." Their first child, Elisabeth, was born a year later. Their son Jean was born five years after Elisabeth.

"When I got married I had never worn makeup nor high-heeled shoes," she says. "I had never been to a restaurant. And I had never been to a hairdresser." For a wedding present, her mother's maid gave her a box with drawers filled with Elizabeth Arden cosmetics. "And you see," she says with a wonderful, generous grin, "I catched up."

She visited New York as a young bride, and Diana Vreeland, then an editor at Vogue, spotted Jacqueline and Edouard having lunch at a French restaurant. Vreeland called her the next day and asked her to be photographed for the magazine.

She was astonished. "I thought that I couldn't be photographed in Vogue looking like a schoolgirl, with my hair in a braid and no makeup. So I went and spent I don't know how many hours to have my makeup and hair done."

When she arrived at the studio, she recalls, Vreeland was aghast. "What have you done to yourself? If you only know how beautiful you were yesterday," she said.

"Aren't I beautiful today?" de Ribes repeats in a voice that sounds like Audrey Hepburn.

"Much less," Vreeland answered.

De Ribes recalls that Vreeland then started to brush her curls flat, to recreate the look of the day before. The photograph has become one of Richard Avedon's most famous portraits.

"Vreeland was the first one to tell me I was beautiful," says de Ribes. "I didn't believe it. I thought she liked strange-looking people, something different," she giggles.

At age 20 her name appeared on the International Best Dressed List. She says it was a total surprise, but admits that such accolades are sometimes a burden. "I remember once I walked into hairdresser Alexandre with my hair down, no makeup, and he was so shocked. Alexandre said, 'Vicomtesse, you can't do that to me. You can't appear looking like this. You disappoint all of us.' " She adds, "I thought that was terrible. If I have to go to a hairdresser all dolled up, then when will I ever relax?" As a result, she rarely visits a salon, preferring to fix her severe chignon herself -- though "I hardly fix it," she says.

The rest of her beauty regimen is equally minimal. She watches her weight, trying not to become too slim. "I can't be very thin and not look tired." At dinner at Le Lion d'Or last weekend she refused nothing but the sauce for her raspberry souffle'. Exercise is simply part of her daily existence -- covering the four floors in her Paris house that has no elevator.

She is just beyond 50 now. "I have no interest in talking about my age," she says brusquely. "I don't imagine myself as old." She says she doesn't worry about getting older. "The only thing that has changed in my life is needing reading glasses."

When she first made the best dressed list, she had two couture outfits. She had made her other clothes herself. "I guess I had the sort of chic that anyone can have without being dressed by haute couture . . . you have it or you don't."

She had endless ideas for clothes, but couldn't sketch them. Her friend Valentino, then a young sketcher at Jean Desses, would come to her house and make drawings from her ideas, then her maids would make them into muslins and finally into dresses. Anonymously, she sent her designs to manufacturers in Paris and New York.

She was afraid for Valentino when he left for Rome to set out on his own. "A few years later I got the first invitation for his collection. I went to see it. I thought often later about Valentino and his courage."

She started going to Saint Laurent when he designed for Christian Dior, not only because she liked his creations but because he let her impose her ideas on his designs. Jacques Rouet, the head of the house of Christian Dior, once complained, "Jacqueline, we can't afford to have you as a client. You destroy every basic pattern, then it takes hours to put them back. Your dress ought to cost 10 times the price." And Betsy Bloomingdale told Women's Wear Daily that when she and de Ribes ordered the same design, the dresses never ended up looking the same.

She says she's never regretted anything she has bought, but felt brief remorse over two embroidered dresses she at first thought were too expensive. "I thought at the time I was doing something close to a sin," she says. "But after they hung in my cupboard and I wore them once or twice . . . I realized th y were masterpieces." She's never shoved anything into the back of her closet unworn, and only once has she regretted wearing something -- a curly wig.

"I just wanted to see myself different, so I bought a wig with short curly hair to go to an opening at the Palais du Chaillot," she says. Audrey Hepburn, who was seated next to her, was shocked at her appearance. "I felt miserable the whole evening. I had worked on it a long time and I couldn't change it. It was terrible." If she ever does a book, that picture will surely be included, she says, laughing.

She has also saved the picture from a party with the Rothschilds at Castle Haar, in Holland, for which guests were told to make costumes for one dollar. "I decided to come as a dame du moyen age. I wore a black sweater and the curtain of my room. I twisted two hangers in my chignon and draped a towel over it for a wimple. The dollar was spent on white powder puffs I used at the de'collete' to imitate swan's down."

The first collection she designed was all cocktail and evening clothes, which now account for two-thirds of her collection. "I felt people would trust me more in evening clothes because they have seen me more in evening clothes." She knows some think she rests all day and goes to splendid parties every night. "People see you at the gala, but what do they know? They see someone with an evening gown, somebody tall with a pointed nose and lots of hair. But who is really interested to find out who you are? They have never seen you en famille, at work, they don't even want to find out -- they judge you from a sight." Later she adds, "I would have died if I had had such a life, only to take care of myself. It would have killed me."

Now her collection includes daytime clothes, "my architectural things," which she designs first by sketching. The evening clothes she designs with the materials in front of her. "I am very sensuelle. I have to touch and drape and feel the weight of the fabric. The only way to have a dress fall well, you have to see the fabric." Fabric makers call on her in Paris, but recently she has created her own prints in Italy.

In her first collection she used some of her own jewelry, but since then she has created extraordinary pieces to complement her clothes. Some have suggested she has only to look in her own wardrobe to find things to copy. But she responds firmly, "Why would I cheat in any way? I have done this because I was trying to create. Besides, I don't own so much to copy from."

Jewelry is an essential part of the collection. "Every dress needs to have its decor. Yet so many beautiful clothes are destroyed because someone had a sapphire parure and they wanted to wear it and the dress didn't go with the jewels, or they had rubies . . . I have seen that all of my life." She will let only someone who buys her clothes purchase her jewelry.

Her clothes are successful when a woman really feels attractive, even seductive, in them, she says, though she is troubled by the word. She was shocked when Christian Dior said, "Sex appeal is the opposite of elegance." She disagrees. "You can be extremely elegant and marvelously sexy. It is just more difficult to manage both."

Jeans are always sexy, she says, and clothes that fit close to the body -- the current fashion rage. "But too tight is difficult to be graceful," she says. "You have to be at ease in your clothes. If you are uncomfortable in your clothes it makes you act funny. And as soon as you are not natural in the way you behave, then you cannot be elegant because you have lost your basic grace."

And there the vicomtesse perches, in her jeans, naturally and marvelously elegant.