"You must be careful to speak more slowly," said Pierre Dux, general administrator of the Comedie Francaise. "Aside from that, the productions we will be bringing to the Kennedy Center are exactly the same as those we present in Paris-the same actors, the same scenery, costumes and props."

The two-week visit of the Comedie Francaise (its first here since 1970) will begin on May 15 with the American premiere of its new production of "Ruy Blaf," a swash-buckling romantic drama by Victor Hugo, as part of the spectacular opening night of the Kennedy Centre's French festival: "Terrace: The Romantic Epoch."

After the festival has ended, the Comedie Francaise will present two other productions: Moliere's "Le Misanthrope" and Feydeau's "A Flea in Her Ear," following tryouts in New York City.

Dux, who has been acting and directing at the Comedie Francaise since 1929-for one-sixth of its 300 year history-gave a press conference yesterday at the French Embassy. His face seemed familiar, partly because he has appeared in many films, including "Is Paris Burning?" and "Z," but even more because of a marked resemblance to Charles deGaulle.

For the Kennedy Center performances, a simultaneous translation system will be available to English-speaking members of the audience, Dux noted-at least, he hopes it will be simultaneous. "We have made trips to the Soviet Union, Japan and South American in recent years," he said, "and I have noticed that sometimes the translator gives a line before the actor-so the people who are listening to the translation laugh first."

There was a touch of pride in his voice when he announced that the company was bringing with it "Le fauteuil de Moliere," the armchair in which Moliere sat while he was performing in "Le Misanthrope" and in which he died after giving his fifth performance of the role. This chair is a symbol of the proud tradition of the company, which is a continuation of the troupe founded by Moliere.

"Parisians will not be able to see "The Ruy Blaf' for more than five months, because we are shipping the scenery and costumes by sea, and that takes two and a half months each way," said Dux. "Perhaps we should have asked the French army to supply air transport." CAPTION:

Picture, Pierre Dux, left, and French Ambassador Francois de Laboulaye, by Harry Naltchayan-The Washington Post