Open Monday through Friday, 11 a.m. to 2:30 p.m. and 5 p.m. to midnight; Saturday and Sunday, 5 p.m. to midnight. AE, MC. Reservations accepted. Food: Feast or diet deliciously Style: The emphasis is on the food Price: A grand $10 meal or a light supper for under $5

"BY THE CIGARS THEY SMOKE, and the composers they love, ye shall know the texture of men's souls," wrote John Galsworthy. But he never ate at Le Gaulois, named after a tough little French cigarette and addicted to insipid light pop music. Nothing tough or insipid, though, about the soul of this new French cafe-restaurant.

This is a restaurant that gives its all to the food, serious food. Frills are minimal - daisies in brown jars, walls decorated with shells or paneled and papered with a colonial-kitchen design. The blue-jeaned waitresses are ingenuous, their enthusiasm outpacing their efficiency.

George Washington University students had discovered Le Gaulois by my first visit, and the packed tables were lively with raves being exchanged and diners telling newcomers not to miss the veal or the quiche or whatever.

Le Gaulois has a something-for-everyone menu, half of it printed, half of it a sheet of daily specials that take advantage of mussels being available or hot weather dictating cold dishes.

If you are wilted by the heat, there is a beautiful chef's salad or often a salmon masked with pale green mayonnaise or a platter of cold beef.

If you want a light supper, try a quiche, or a fragile seafood crepe nearly rupturing with scallops, shrimp, king crab and mushrooms in a winey cream sauce.

If you are on a diet, you are really in luck at Le Gaulois, for here are three cuisine minceur dishes which can make you feel privileged to be dieting. A rockfish in papillote - actually, in aluminum foil - is a thick, juicy filet steamed with tomato wedges, potatoes and slices of lemon, pungent with dill and black pepper. Butter, oil thickeners are not missed; the lightness and purity of the dish render tham superfluous. Rata-touille - served hot or cold - is listed as a minceur dish; again, the familiar olive oil undercurrent is missing but not missed. As for the braised veal with orange sauce, I heard raves my first visit, but found on subsequent visits that its price had been raised by $2, and it was unavailable anyaway.

If you have no special needs other than a good meal, concentrate on the daily specials. You will probable find cold marinated vegetables or fruit salads as first courses; as main courses, mussels, fish, lamb, and elaborate ground veal preparations such as veal pojarsky or florentine with a pastry wrapping and madeira saucing.

As for appetizers, the pate is a rough-cut loaf, heavily flavored with liver but light on seasonings. The borsch, on the other hand, is roundly seasoned and tart, but based on a weak broth. The vinaigrette at Le Gaulois is understated and resists overwhelming the velvety brains or firm mushrooms, so ordering anything vinaigrette as a first course is a sound idea.

Fish - certainly order fish. Not only is it chosen well and cooked beautifully, it is sauced with the likes of an airy wine and cream sauce.Veal dishes are robust, sometimes with a translucent brown mushroom sauce or a nutmeg-tinged sour cream sauce. And if you like homey dishes, order something like stuffed peppers, homemade sausage or pot au feu. Along-side main dishes come fresh vegetables, maybe cauliflower permeated with butter, or superior crusty sauteed potatoes, chewy fragrant saffron rice or seeded cucumber cresents in sour cream.

I can't report on many of the desserts, since the relaxed service seldom left me time for a third course. But if you last, you certainly should try the almond tart, flaking at the slightest touch, filled with lightly sweetened almond paste. The strawberry tart is less delectable, being heavy of crust and slightly soggy.

Portions are large enough that dessert tends to be superfluous unless you go just for dessert and espresso.

Though there is a full bar, the liquid mainstay seems to be carafes of wine - Inglenook white and Sebastiani red - at $4.50. With main dishes at $2 to $7, almost all under $5, Le Gaulois is a good place to go when you don't want just a cafe snack, you don't want to spend much, you don't want to dress up, but you want good food anyway.