PARIS - Heady and intense, expensive, delicate and robust, it is rationed by the spoonful. Caviar, the lightly salted eggs of the sturgeon found in the Caspian Sea, sparkles and tingles on the tongue, conjuring up fantasies of sensuousness, celebration, ultimate extravagance.
So what could be better than to begin the fin-de-siecle celebration at the new Petrossian Restaurant, right above the famed caviar specialty shop that has graced the Boulevard La Tour Maubourg since 1920. The restaurant, decked out in mirrors and shades of gray, with a youthful staff of varied experience, is probably one of the best spots to study - if that is a word mere mortals could use - this delicacy.
On a recent weekday evening we feasted on a caviar tasting called ''Le Prince Gourmet,'' which included nothing less than 20 grams (not much if you are thinking in terms of apples and oranges, but a lot in terms of caviar) of the three basic varieties of Iranian and Russian caviars: beluga, ossetra and sevruga. One could create a feast on one's own turf, but how much better it is when served out of glass and silver caviar carriers while someone else makes the blinis and toast and keeps them warm. (If you like to eat a lot of caviar, you won't pay much more here than you would in the shop below, so why not take advantage of the service?)
We had our caviar with a fine Veuve Clicquot Champagne. The beluga - the largest variety and the most expensive - was delightful. Nothing beats that gush of purity, that moment you hold the grains in your mouth, crush them with the tongue and explode their essence onto your palate. But I remain faithful to ossetra, with its subtle, nutty flavor. The eggs always seem firmer, with no trace of ''fishiness'' that one sometimes finds in other varieties. And I would never turn up my nose at Petrossian's sevruga, the smallest of the trio: young, fresh, almost lactic in flavor.
The caviar was served with plump and puffy blinis, toast and a touch of creme fraiche, all one needs - if anything - to accompany the precious mouthfuls. for every budget While a full tasting begins at about 1,080 francs ($170) a person, Petrossian has something for every budget. The noncaviar menu needs some attention, however, because the dishes' names can be confusing. One could end up with three courses of cured, salted fish, as I did when I ordered dishes that gave no hint of containing smoked fish and ended up being almost nothing but.
The best bet was an appetizer of six little tastes (five at lunch), ''Assiette de Tentations,'' that included smoked and marinated sturgeon topped with a sherry jelly and sevruga caviar, and an excellent fish tartare on beet chips. But many of the main courses - the steamed St. Pierre, for example - were far from memorable. And some dishes I would not even want to gamble on: Reblochon cheese and langoustines? Two of my favorite foods, but not together!
Philippe Conticini, the pastry chef, has some bright ideas here, but they don't really get a chance to shine - many need a 3-D view to be appreciated and would best be served in a glass vessel but are hidden in porcelain bowls. His creations range from audacious to delicious to wacky. The finest was his pistachio cream paired with a rich cherry coulis offset by a sprinkling of salted pistachios.
18 Boulevard La Tour Maubourg
Credit cards: American Express and Visa. 320-franc tasting menu. A la carte, beginning at 350 francs, not including wine or service.