150 Connecticutt Ave. NW. 296-7972. L $11-$21, D $13.50-$26. L daily ex Sat. D daily. Closed Sun. AE, CB, DC, MC, V. Res req. Free PMI parking. Full bar.

There is a lot to be said for maturity, and it certainly can be said about Le Lion d'Or, the senior among Washington's top French restaurants. In its clubby dining room there is the bustle of tableside finishing touches. While the service is sometimes impersonal, it is always polished. Order from the daily specials--or what you can remember from the chef's recitation. Whether as simple as perfect crab in a suave and pungent remoulade or as complex as truffled, hot rabbit p.at,e in a crust, the food is likely to be excellent. Main dishes are the stars: lamb fillet with mustard seed for serious meat eaters, veal medallions topped with fresh foie gras and basil-flecked cream for glamor-seekers, squab with wild mushrooms, baby salmon or fresh shrimp for those who appreciate a rarity. It's an insiders' place, where the beautiful people may get more beautiful food. But Le Lion d'Or has worn well. By the standards of its competitors, it is not outlandishly expensive, but it can be outlandishly good.