Open for lunch Monday through Friday, 11:30 a.m. to 2:30 p.m.; for dinner Monday through Thursday, 5:30 to 10 p.m., Friday and Saturday until 10:30 p.m. Bistro menu available all day. Disco dancing from 10 p.m., Tuesday through Saturday. AE, MC, V. Reservations. Prices: Main courses at dinner $6.25 to $14, averaging under $10. Full dinner with wine, tax and tip averages $20. Fixed-price, five-course dinner Monday through thursday, 5:30 to 7 p.m., for $9.50.

Yes, there is life after disco. Claude's, the second restaurant to occupy its glitzy space-age dining-and-disco premises, proves that there is even life before disco. While this second incarnation includes late-night dancing, Claude's has turned it into a very good continental restaurant where the flashy setting is supported by a serious kitchen.

First, about that setting. At a glance it looks like a dim, sleekly appointed space ship, its walls wearing giant metal sunburst sculptures, the ceiling lit from large recessed circles rimmed with hanging greenery, leaving you wondering how anybody waters the plants. While all the seats are plush and comfortable, most intriguing are the curved booths set like caves in the walls, with tube lights and spotlights on dimmers. The dancing is in an adjacent room, beyond plexiglass walls.

A warm greeting and warm bread begin your evening. The bread is only mediocre French bread, and the flowers on the table are carelessly arranged, but this is a restaurant of solid satisfaction rather than of thrills.

The wine list, for instance, is small and includes standardized shipper brands without vintages; the best one can say about it is that it is not noticeably overpriced. The menu runs the usual gamut of snails, pate, onion soup, coq au vin, coquille St. Jacques, veal Francaise and steak au poivre. Nothing sounds irresistible, although the list of daily specials ventures into several fresh fish whose preparations are named after Emmanuel, St. Tropez and Cleopatra. What first attracts one to the menu, though, are some of the very reasonable prices. True, snails are $4 and the daily special main courses often run over $10. Salads are around $3. But pate is $2.75, salmon or veal under $9, most desserts under $2. While fresh scallops appeared among the specials one day at $11, coquille St. Jacques, probably frozen but nearly as good, was only $7.25.

What reinfores the attraction is the high quality of most of the food. Among the appetizers is "avocado et champignons vinaigrette, $2.50." It needs a better sales pitch, for in actuality it is a perfectly ripe avocado, thinly sliced and fanned out, bordered by a delicious marinated mixture of diced mushrooms and tomatoes. Extremely pretty and fresh, it is a delightful summer appetizer. Likewise, the smoked salmon is hand-sliced, excellent cured fish, equivalent to what many restaurants charge double its $4.50, though one day it was clumsily arranged on iceberg lettuce and accompanied by flabby, soggy toast. Another day its presentation was impeccable. Even standard onion soup is unexpectedly fine, the broth rich and meaty, faintly sweet from the proper slow-browning of onions, its topping an ooze of good cheese.The thick slices of unctuous liver pate and the buttered and garlicked shrimp with artichokes reinforced positive first impressions of the Kitchen; only an alcohol-sharp lobster bisque was substandard.

Among main courses, fish is prominent, particularly on the daily specials. Every day you can find sole, scallops in a nice oceanic cream sauce and salmon with hollandaise, but the freshest (and most expensive) seafoods are the changing ones. Sea trout one day was lightly crusted with flour and sauteed, the ideal crisp and moist contrast one hopes for fish, and garnished with sauteed mushrooms and sliced artichoke bottoms. Most surprising was a lobster tail -- $14 -- that, despite having probably been frozen, was moist and delicate, covered by a lemony crab imperial with just sufficient capers and pimento. While lobster tails don't play in the same league with fresh Maine lobster, and the portion is bound to be small, it was as good a lobster tail dish as I have tasted. Meat dishes are primarily veal and steaks. The veal has the pallor of quality and is carefully cooked. Calves liver is subtle and tender meat topped with a tangle of bacon. And steak with Bearnaise sauce is hefty in quantity and impressive in quality, particulary for $10.25. It is beef with chewiness to it, not overtenderized, thickly cut, precisely trimmed and well seared, with a buttery thick sauce. The best of the vegetables are cottage fried potatoes, thick crunchy slices. And twice I have been served fresh green beans, well seasoned and, though not nouvelle-cuisine crisp, certainly short of mushy.

Desserts are, like the main courses, predictable choices: chocolate mousse, fruit tarts, coffee custard and cheesecake that is not made in-house. But the fruit tarts are a notch above those of most French restaurants, well-browned puff pastry and just a touch of custard, ripe fruits and a glaze of fruit jam rather than edible plastic. One day the chocolate mousse equaled the tarts' quality, being pale chocolate whipped cream flavored with bittersweet flakes. But another time it was dark and gritty, stiff from being refrigerated too long.

We have grown to expect untutored service in new restaurants, but there, too Claude's surprises. The waiters are experienced, and the service has been not only suave, but exceedingly attentive. Even the busboys have bothered to ask how everything was. The waiters have been informed about the preparation and ingredients of the dishes and were forthcoming about which were particularly good. Attentiveness continued right through the farewell.

The restaurant attempts to do a lot of things -- to serve light meals all day as well as full-course dinners, to welcome formal dining as well as shirtsleeves, to permit quiet leisure along with late-night disco. It might seem too big a chunk for one bit, but the kitchen does no more than it can handle capably. And few other restaurants, particularly in the Maryland suburbs, offer wining and dining for under $20 so well conducted as at Claude's.