Open for dinner at 8 p.m. on Friday and Saturday only. MC, V. Personal checks accepted. Reservations required. Prices: fixed-price dinners at $30 per person, including wine. Parking in front. Wine only.

"Come between 8 and 8:15," someone called the

Baron had told them on the phone, and they've

begun to arrive. Well-dressed couples, drawn by

fanciful ads in local papers, climb from their cars.

"Is this the place?" one woman murmurs, a little ill at ease. A French restaurant in this industrial warehouse section of Rockville, an area best known for auto body work? They stand contemplating an unmarked and not-so-renovated garage, whose only external concession to its new life as a restaurant is a small blue canopy. "Is this the Caf,e Le Cabotin?" the woman asks again.

It is. And there are more surprises inside. These hesitant guests will soon find themselves hanging up their own coats, serving their own wine, helping themselves to seconds of bread and soup, pouring their own coffee, providing some of the entertainment and paying for the privilege--as of now, $30 per person plus tax and tip. On the other hand, by the time the evening is over they will know not just the waiter, but all the other guests by first name, which can't be said for many other restaurants.

To understand Le Cabotin you have to understand the owners (and sole staff members), the Baron and Francoise, a >husband and wife team that has been in business here since May. She is menu planner, shopper, chef. He, an ex-actor, writes the unconventional newspaper ads, makes the reservations, greets the guests, serves as the only waiter and, most important, infuses Le Cabotin with the sense of theater that is its hallmark. Bearded, slightly stooped, decked out in black tails and walking stick, the Baron is a blend of illusions. The caf,e is his brainchild, outlet, stage, kingdom. Here he's author, impresario, director, performer, prime minister. Le Cabotin's audacity is his audacity, for better or for worse.

The look of the place is pure theater, too. Except for an immense, two-story-high mural of a seaside village covering one long wall of the cavernous ex-garage (another product of the multi-talented Francoise), the decorations are spare, just right for the Baron's legerdemain. Illusions need room.

The caf,e is open only on Friday and Saturday evenings, and occasionally not even then. Advance reservations are a must. Francoise decides on the menu early in the week (no options, except perhaps for a choice of soups). Dinner consists of appetizer, soup, entree, vegetable, cheeses and dessert, with aperitifs and wine included in the fixed price.

Dinner at Le Cabotin is a three-hour happening. The first stage is a mingling of the guests over aperitifs at the bar. Later the Baron seats people, generally three couples to a table. Working by herself in the kitchen, Francoise needs time between courses, time that's filled by the Baron in a series of diversions that involve much dimming of the lights, offstage recitations and closed-circuit TV. With Fellini-like flair, the Baron manages to ease the audience into the act. Extraordinarily, everyone seems to respond to his bag of tricks. He may narrate a fantasy in which the guests find themselves among the characters. Or appear on a TV screen, delivering a nonsensical news report. Or ask people to take turns reading aloud, or suggest they walk around and hug their neighbors. It's a strange, insulated world, in which we sometimes felt like the island guests in "Key Largo." With our dining critics' assumed names and occupations (Bogart would have been proud), we felt right at home in this place where pretense and illusion are so essential. After dinner, everyone is encouraged to linger over coffee--again, the effort to create the sense of an intimate party, not just dinner in a restaurant.

But it is a restaurant, and this is primarily a report on dining, not on reciting or mingling. So what about the food? First, a caveat: because of the vagaries of the caf,e's openings and closings, we were able to sample only one meal in a two- week period, so consider this a tentative report. One thing is clear: Francoise is a skilled cook, and she seems careful to start with top-quality raw materials. But she's all alone out there in the kitchen, which makes it difficult to undertake complex dishes.

Here's a rundown of our single dinner. A cold appetizer plate of shrimp and smoked sturgeon, neither more nor less than what you'd buy at the deli counter, served with a zippy piquant sauce. Impeccably fresh, carefully handled pain d'epi from the Bread Oven. Two creamed soups, one broccoli, the other a pureed, turnip-based mixture, both subtly flavored and impressively balanced. Sliced beef tenderloin of the highest quality, served in its natural juices with a scattering of sliced mushrooms. Braised celery, gently done to retain life. An assortment of cheeses. An adequate but unexceptional dessert pastry, bought elsewhere. And coffee. The wine? A fair-to-poor jug white, and a very ordinary beaujolais.

A pleasant enough meal, but not a memorable one. What Francoise did herself, she did very well. The central question is whether what she does is enough. At least at this stage, it's safe to say that the food isn't what makes Le Cabotin special.

This is a restaurant like few others, one that could serve as a Rorschach test for diners. An advocate of Le Cabotin might judge it like this: "Here, dining out takes on a whole new dimension. Besides dinner, you get an entire evening of good fellowship, entertainment, theater, a great escape. It's like going to a dinner party at the home of a clever and unconventional host. And the Baron is delightfully wacky and whimsical."

A detractor might put it this way. "At these prices, I want a more varied and complex cuisine, and I want proper, traditional service. Besides, I'm a private person who wants to be anonymous when I go out to dinner. If I wanted theater I'd go to a show afterward. And I think the Baron's shenanigans are more self-indulgent than whimsical."

Whatever your reaction to this strange place, maybe there's something to be said for adding a little zaniness and cheek to Washington's restaurant world.