The 18th-century French, with their gilt-edged brocades and milk-white porcelains, may have elevated the art of luxury to previously unknown heights. But in midtown Manhattan, where opulence in this century seemingly knows no bounds, modern-day Marie Antoinettes seem to have multiplied by the thousands.

At least that's what the owners of Caviar Petrossian (58th and Seventh Avenue) have discovered. A spokesman for the the new restaurant, opened about a month ago in elegant Erte' decorated quarters, estimates that the establishment has already sold "thousands and thousands" of grams of caviar -- Beluga, Ossetra and Sevruga. "We really haven't been able to count it all."

Of course, there has never been caviar like Petrossian caviar, according to those who know. Since the fall of czarist Russia, this French family has maintained the exclusive rights to sturgeon eggs fresh from the Caspian Sea. Should caviar be just another fishy byproduct to your palate, you might try the wild smoked salmon, foie gras or truffles. Or Perrier Joet champagne.

Who goes there? Candice Bergen, Gordon Getty, Malcolm Forbes.

Cost? About a dollar a gram for Beluga, or $120 for dinner for two, depending on how much caviar you can eat in one sitting.

Speaking of pampered stomachs, French artist Arman, known for the past 20 years for his assemblages of similar or identical objects, has a show up this month that may possibly upset a few.

In "Arman: The Day After," the artist has recreated what he imagines our interiors would look like post-bomb. First he set a grouping of bourgeois furnishings on fire in his backyard. Then he cast the charred remnants in bronze and moved them across the Atlantic to an elegant setting in the Marisa del Re Gallery (41 E. 57th St.), along with photographs of the immolation.

The furniture? Louis XV, of course. "Reproductions," a gallery spokesman pointed out. "He wouldn't destroy originals."

Deluxe may be de rigueur uptown, but downtown is another world. Take Princess Pamela, a jazz vocalist who won wide favor in the 1960s. The vivacious chanteuse has come back. She's serving ribs, fried chicken, greens and grits upstairs in a memorabilia-filled room at Princess Pamela: Live Jazz and Southern Food (Tenth Street and First Avenue; call ahead).

Like the folks at Petrossian, the Princess cannot keep count of the quantity she sells. "I don't know how many ribs I sell," she said the other day, standing next to a picture of herself and Ethel Kennedy in Sun Valley. "But people sure do like my chicken." Many nights she sings after 11, but every night she greets her guests as though they were long lost friends.

"I am sooo glad to see you," she told a total stranger recently.

Who goes? Jedd Garet, Julian Schnabel, Steve Martin, John Lory.

How much? "If you have to ask, you can't afford me!"