Saturday night was round one of a two-week marathon of French fashion events beginning at Tyson's Corner Bloomingdale's, and although the party was a hit, the clothes were not.

About 350 subscribers paid $25 each for the Washington Opera Guild benefit and a chance to meet designers Pierre Cardin, Jean Charles de Castelbajac and Thierry Mugler. Costume curator Yvonne Deslandres brought couture garments from the Musee du Costume in Paris (insured for over one-half million dollars) and a collection of passamenteric, including items from the household of Marie Antoinette.

There was a slide show from Paris ready-to-wear collections, narrated by Women's Wear Daily assistant publisher June Weir and an exhibit of photographs by avant-garde Paris fashion photographers Guy Bourdin and Helmut Newton.

But most of the guests were simply not ready for such high-fashion profundities as palace-guard or storm-trooper outfits. There were guffaws, particularly from the men in the audience, over a slide that showed ankle-high boots and striped hose, and out-right cackles when Weir said that "Yves Saint Laurent certainly knows how to flatter a woman" as a red lumberjack jacket and skirt flashed on the screen.

"We just want to show you what's happening in Paris," explained Bloomingdale's board chairman Marvin Traub. "You are not supposed to, necessarily, like the clothes."

Opera Guild chairman Mrs. Edward Bruce tried to beg off the questions of her response to the clothes saying, "I'm an opera person not a fashion person." She did bring home one padded-shoulder jacket this season she said which her husband made her take back. "I think if you get one pair of black leather pants you can be set for this season," concluded Bruce, who wasn't sure if she would buy a pair herself.

Dr. Jane Fong of the Psychiatric Institute found the clothes "sado-masochistic as well as seductive."

More than one guest looked with relief at the vintage French designs mounted on mannequins in the store. "These are gorgeous," said a government analyst, pointing to a group of Chanel dresses. "The things in the show were awful. You have to be tall and skinny to wear them and even so . . . I think you'd be hauled off to St. Elizabeth's."

And then there was French designer Thierry Mugler who missed out on an evening at Pisces. The private Georgetown club notably would not have let him in as he was - wearing his own design, a white, gold-buttoned suit, tieless, and looking as someone noted, not unlike a chef off duty.