THE `R&D LAB' OF HIGH FASHION

Couture is the French word for sewing. Haute is the word for high. Haute couture - high sewing - is France's venerable made-to-order clothing industry started in 1850 by an Englishman, Charles Frederick Worth.

To qualify as one of the 21 couturiers sanctioned by the Chambre Syndicale de la Couture Parisienne, the governing body, a couturier must employ a minimum of 20 workers in its atelier, present a collection of at least 75 outfits semiannually, and show it at least 45 times a year in a special area of the house. Customers - estimated by some at 200 to 400 but officially at 3,000 by the Chambre Syndicale - are given a minimum of two fittings. Blouses start at $4,000, suits range from $12,000 to $23,000, and

a beaded ballgown can cost as much as $100,000.

A French government commission is studying the rules of haute couture. Next month it is expected to ease the requirements, welcoming new members, and with them an injection of fresh energy into the group long considered the research-and-development laboratory of international fashion.

As an experiment this season, ready-to-wear designer Thierry Mugler presented a mix of one-of-a-kind pieces and made-to-order designs. His presence, along with Valentino and Gianni Versace, the two Italians who continue to be forces in haute couture despite their de facto status, would seem to offer further proof that the Chambre Syndical's policy of welcoming all comers has made Paris the undisputed capital of international fashion. At least for the moment.