Arlington has its Little Vietnam, Adams-Morgan has its Little Latin America, and now Bethesda is turning into La Petite France. Earlier this season Le Marmiton was added to the mix, and now two more restaurants, one French -- Cafe Al,an -- and one near-French -- The Restaurant in Bethesda -- have concentrated in the neighborhood. If neither is likely to draw Francophiles from downtown, both are worth knowing for their fetching charms and eager attempts to please. THE RESTAURANT IN BETHESDA

7820 Norfolk Ave., Bethesda. 657-1607. Open for lunch Monday through Friday 11:30 to 2:30 p.m., for dinner 6 to 10 p.m.; Saturday from 5:30 to 10 p.m. Closed Sunday. AE, V, MC, DC, Choice. Reservations suggested. Prices: Appetizers $2.25 to $5.75, entrees $7.95 to $12.75, desserts $1.95 to $3.50. Dinner with wine, tax and tip about $25 to $35 a person.

Whimsy is in short supply in Washington's French restaurants; in most cases they take themselves too seriously. Now, along comes one that has enough tongue in cheek to call itself The Restaurant in Bethesda (and be sure to use the entire name if you are trying to get the number from information).

Some of the waiters are so traditionally French that in some cases their accents are thicker than the steaks. Once whatever accent barrier is surmounted, however, this restaurant has some of the most concerned service in town -- which makes up significantly for the erratic pace of the kitchen.

A welcoming restaurant, quaint and comely, with prices so modest that a filet mignon with two sauces tops the price list at $11.75, The Restaurant in Bethesda is an awfully nice place, though I must warn you that the least interesting part of it is the food. Only one dish has stood out among my visits. Terrinf Vegetable Patricia is an appetizer that avoids the flaws of most vegetable terrines. Its ribbons of carrot, broccoli and such are not pur,eed to a paste, but left with some texture to bite, and a lightness as well. And each vegetable layer has a good rich individualistic vegetable flavor. It is a fine terrine, much better than its sour cold watercress sauce.

Other appetizers sound equally interesting -- chicken liver and lettuce salad with champagne vinegar dressing, oyster gratin on spinach with champagne sauce, mousse of trout in puff pastry with hollandaise -- and there are the everyday oysters and snails as well. But from the simplest (caesar salad with oil missing from the cheese-garlic-anchovy dressing) to the most complicated (gummy thick trout mousse in a light but overbrowned puff pastry) there are insufficiencies. You get the impression the chef is within sight of capability, but lets the details slip. The oyster gratin would have been fine -- and a fine value at $5 -- if the oysters tasted fresher and plumper; and even steak tartare missed because it was outlandishly overseasoned.

Main dishes were less obviously flawed, just undistinguished. A trout boned and stuffed with shrimp was plain and decent, with no culinary flourishes (or apparent binder for the stuffing), and lamb provencale was a well-seasoned and crusty lamb steak marred by gristle and chewiness and drenched in garlic-parsley butter. Fish, too, have been aswim in butter, in particular a shad that was further sullied by a roe-souffl,e topping that was a brilliant idea but tasted merely like salted whipped egg whites with bits of roe. Filet of beef was, like the fish, carefully cooked. But the brown sauce and thick, strong b,earnaise, were ordinary, and the meat lacked juiciness. With main dishes come similarly erratic vegetables, perhaps a stewy mush of ratatouille and rice with some chewy and hardened grains, or sometimes a delicious squash au gratin.

Dessert is this kitchen's major effort, and there are trays of pastries looking worthy of any Parisian patisserie. All are made in house, and some are exceptionally good, particularly the thinnest of cookie shells cupping a soft, creamy and very chocolaty mousse. Occasionally there is a too-bitter lime tart or a passion fruit bavarois or mango tart that lacks the taste of the fruit. But other pastries -- particularly the mousse-layered and creamy tortes -- are impressive, and you can try an assortment as a Fireworks of Desserts for a mere $3.50. The wine list, too, while indifferent in its scope, is very low priced.

The Restaurant in Bethesda is erratic in its timing, quality of ingredients and culinary skills. In fact, the average is not exciting. But given the prices -- and the occasionally dashing preparations -- it is a cheering addition to its neighborhood. CAFE ALAN

7141 Wisconsin Ave., Bethesda. 654-5055. Open for lunch Monday through Friday 11:30 to 2:30 p.m., for dinner 6 to 10 p.m. Monday through Thursday, until 11 p.m. Friday and Saturday. Closed Sunday. AE, MC, V, DC, CB. Reservations suggested. Prices at lunch, appetizers $2.95 to $6.25, entrees (daily specials) $8.50 to $9.50, desserts $2.95 to $3.25; at dinner, appetizers $3.25 to $7.50, entrees $12.95 to $34, desserts $3.25 to $4.50. Dinner with wine, tax and tip about $35 to $40 a person.

Cafe Alan takes itself more seriously. Not only is it more formal but its menu is longer, more luxurious and more expensive. And like its neighbor, Cafe Al,an has very pleasant service, which makes up for ordinary food. The best of the appetizers I have tried were pastas, one with smoked salmon and another with tiny fresh clams and parsley; and at $4.25 to $4.75, they were also surprising values. Otherwise, the same old story: saut,eed wild mushrooms tasting fine but left sandy, steamed oysters pleasantly sauced but small and lacking sweetness. The emphasis on presentation is a treat to the eye, and there is careful enough cooking of the seafoods, grilled fish, steaks, roasts. There are interesting menu listings such as breast of chicken with goat cheese and prosciutto, or grilled salmon with cherry butter. But I haven't found a sauce to remember, no taste to perk interest. Even the vegetables are arranged with precision and accompanied by an unmolded savory custard. But for all its taste that custard could be anything from turnip to potato without one knowing which. Wine prices are high, a few in the stellar reaches that make one wonder who would buy a $100 wine for such a meal.

You can end with a high and pretty souffl,e of little lightness or flavor, or perhaps a beautifully decorated chocolate mousse on a two-tone lacy web of sauce but with sweetness its most prominent taste.

Here is a most pleasant restaurant, but with a kitchen more notable for its visual artistry than for its culinary distinction.