RUY BLAS, averse play in five acts by Victor Hugo, directed by Jacques Destoop, costumes and sets by the Comedie Francaise, assistant director Pierre-Oliver Scotto, lighting and by Serge Apruzzese, music by Jacques Destoop and Pierre-Oliver Scotto and Michel Frantz. With Jacques Eyser, Bernard Dheran, Michel Duchaussoy, Jacques Destoop Rene Arrieu, Alain Pralon. Francois Beaulieu, Jean-Paul Moulinot, Jean-Francois Remi, Georges Audoubert, Georges Riquier, Phillippe Rondest, Guy Michel, Jeann le Poulan, Annie Ducau, Denise Gence, Genevieve Casile, Paule Noelle. The Kennedy Center, with the cooperation of L'Association Francaise Pour L'Action Artistique presents Comedie Francaise, May 15-20.

They are calling it "The Romantic Epoch," and any skeptics who suppose that this is just one of those arbitrary, academic rubrics that historians love to adorn epochs with should check out Victor Hugo's "Ruy Blas."

It is hard to believe one play could contain so many fiery declarations of passion, grief and malice, or so many unabashedly romantic plot conventions - a commoner in love with a queen, mistaken identity, jealousy, revenge, a duel, a secret hiding place, secret messages, poison, and coincidences that pile up like rush-hour traffic on M Street.

More remarkable still is the pleasure of finding these shabby conventions alongside passages of rich dramatic verse and an intriguing assault on political corruption and class tyranny. Nowadays, scarely anyone but Frenchmen and students of French literature read any of The vast Hugo output beyond "Les Miserables" (if that), but "Ruy Blas," after a static act and a half or so, turns out to be a surprisingly shrewd and lively piece of work.

The main attraction, however, is not the play but the performance - by a company that claims a more or less direct institutional descent from the actors who worked under Moliere 300 years ago.

The members of Comedie Francaise have not changed their methods much these last few centuries - at any rate, that's the impression they are happy to convey. Striking grand, statuesque postures, they speak with booming voices and play every emotion right to the hilt.

Several elements of the production give the appearance of actually being as old as the company - including the dark, musty, decaying curtains arrayed to the right and left (whose ancient look probably means they came off the mill about six months ago). And in the lobby outside stands a chair in which Moliere is said to have suffered the first of the tubercular attacks that led to his death.

So there is a time-machine aspect, a living museum flavor, to watching the Comedie Francaise. But there is also a technical wrinkle for nonFrench-speakers.

Little portable radios and earphones with simultaneous translations are provided, along with an act-by-act plot synopsis. The translations, rendered live by one male and one female translator, are nicely underacted - but the experience takes some getting used to, and even then gives you the feeling of looking into museum diorama rather than being in a theater.

At "Ruy Blas," the best compromise may be to use the earphones for the talky, expository Acts One and Two, before the intermission, and make do with the synopses for the three more self-explanatory acts that follow.

In those acts, fortunately, two wonderfully brash and vivid comic actors, Alain Pralon as the Robin Hood figure Don Cesar, and Jacques Eyser as the jealous old fop Don Guritan, move tocenter stage.

In these performances, we are undoubtedly getting a preview of next week's coming attractions - the comedies (Feydeau's "Flea in Her Ear" and Moliere's "Misanthrope") for which the Comedie is known.

THE PLOT: A spanish commoner, Ruy Blas, dares to fall in love with his queen and, to show it, anonymously deposits a flowr on the park bench she passes every day. She, left alone by an indiffernet king (off wolf-hunting while his empire crumbles), is touched by the flower, although not knowing its source.

By coincidence, the queen has exiled Ruy's master, the evil Don Saluste, for refusing to marry the servant girl he has made pregnant. So Don Salluste, on the eve of his banishment, sets up Ruy as his long-lost cousin Don Caesar (taking care first to remove the real Don Caesar from the scene) and asks only that Ruy agree in return to perform an unspecified mission at an unspecified time in the future.

As a noble, Ruy is such a success that (covertly assisted by his admiring queen) he rises through the ranks with a rapidity that might have driven the younger Pitt into a jealous rage. Soon he is running the country (running it very nicely too), and when the opportunity arises for him to acknowledge his love for the queen, he does so and she responds favorably.

Then Don Salluste returns and demands Ruy's help - threatening blackmail - in his vengeful plot against the queen. Don Caesar also returns. Secret messages are sent an (as will happen with secret messages) misplaced. Finally Don Salluste arranges for the queen and Ruy to be exposed as lovers, and exposes Ruy as a commoner.

Ruy Blas takes poison but dies in his queen's arms. CAPTION: Picture 1, Countess Isabella de Lasteyrie du Saillant, Jean-Phillippe Lecat and Ambassador de Laboulaye, by Harry Naltchayan - The Washington Post; Picture 2, Genevieve Casile and Francois Beaulieu; by Agence de Presse Bernard