More than any other restaurant in the last half dozen years, Le Lion d'Or has moved Washington into the big leagues, and it just keeps getting better. No other in town serves fresh truffles in its sauces, fresh foie gras with its veal or beef. No other restaurant serves rare breast of duck. No pate in town compares with its hot rabbit pate. Le Lion d'Or serves fresh shrimp, perfectly cooked, in a warm, buttery dill sauce, and whole baby rockfish consummately baked in a flaky puff pastry. Its ingredients are impeccable, its daily specials increasingly unique. Trout stuffed with the most airy fish mousse, complemented by a froth of a champagne sauce. Wild boar heavily marinated and juniper-scented, in a powerful winey sauce, arranged like a picture with browned apple quarters and lentils. Only gratin de homard has disappointed, the lobster too chewy and the sauce less airy than the others. Le Lion d'Or seasons dishes - lamb with eggplant and fennel, for instance - with force, and carries that off valorously. The elaborate attention carries through to garnishes, to salads, to a cheese tray filled with seven in perfect condition, to some of the finest desserts this town sees. The orange souffle is the lightest puff, bursting with orange bits and liqueur. Bittersweet chocolate mousse du chat is delicately sauced with moncha. Jean-Pierre cake is a melt of nutted cake layers with butter creams and mousses, no flour at all. Even the tarts are, at last, quite good. This culinary grandeur is absorbed in a dining room of striped walls and soft chairs, handsome if not original, fairly close and noisy on a busy day (which is every day). Service is well-oiled, as smooth as any in town. The wine list stands out, being an in-depth list with fair prices, many particularly tempting in the $12 to $14 range, and a smaller list that is in general more expensive but including an excellent Chambolle Musigny '71 at $12. Le Lion d'Or, when all its assets are totaled to make an evening that can be extraordinary, comes as close as we have to fine dining in the French tradition.