The elegant decor is the work of a designer imported by the French-based Sofitel hotel chain and its parent company, Accor, which spared no expense to transform the long-vacant 12-story Shoreham office building into a 237-room hotel that is a showcase example of 1920s Art Deco style.

The building has a rich pedigree. Once a town house where President Andrew Johnson briefly lived, the site was purchased in 1880 by Levi P. Morton (1824-1920). He razed it and built a hotel on the site, which he named after his birthplace of Shoreham, Vt. Morton, who served one term in Congress as a New York Republican from 1879 to 1881, later became minister to France. (There, he accepted the Statue of Liberty as a gift of the French government on July 4, 1884.) He also served as vice president under Benjamin Harrison and as governor of New York.

But we’re talking dining experiences here and not history or architecture, so let’s deal with the bad news first. The service can range from atrocious to merely annoying. On the first of four visits, along with three colleagues, we waited for 25 minutes at lunch without sighting so much as a busboy to offer us bread and water, let alone a waiter to take our orders. At that point, our patience exhausted, we left for another restaurant.

I gave the restaurant the benefit of the doubt since it was its first week of operation. When I returned three weeks later, the service had improved, but I still encountered glitches in each of three subsequent visits at breakfast, lunch and dinner.

At breakfast, for example, the banana oatmeal brulee I ordered turned out to be granola, not oatmeal. Service at lunch with a colleague was so leisurely that our meal dragged on for an hour and 45 minutes, and I was charged for an iced tea I didn’t receive. At dinner last Friday, I ordered a second glass of wine, which never appeared until I called over the maitre ‘d, who, to his credit, didn’t charge me for it.

Then there are the prices. Sacre bleu! Lunch with a colleague — appetizer, main course, dessert and coffee, but no alcoholic drinks — came to $134 with tax and tip, while a three-course dinner with my wife, including a glass of wine apiece — the third was on the house — brought a bill of just under $180. Breakfast was a bargain at only $20 for one.

Such astronomical prices may be the norm on the rue de Rivoli, but this is Washington, D.C., and the Dow Jones is falling like a bagatelle dropped from the Eiffel Tower. I question whether local diners will tolerate prices that include $14 soups, $22 appetizers and $36 main courses at dinner, with luncheon prices only slightly lower.

Now, for the good news. The food is, with a few exceptions, incredibly good. Consulting Chef Antoine Westermann supervises the three young chefs in the kitchen. (Westermann’s own restaurant in Strasbourg, France, boasts three Michelin stars. Interestingly, the only other D.C. chef who can boast of Michelin stars is just down the street, Gerard Pangaud at Gerard’s Place; he was in for lunch the other day.)

Westermann’s influence is apparent in the cooking of Executive Chef Philippe Piel, Sous Chef Antony Clemot and Pastry Chef Romain Renard. Piel is only 33 and his two colleagues are 29 and 24 respectively, but they spent years learning their trade in French culinary schools and top-rated restaurants in France and around the world.

The food and presentation are dazzling, from the basket of crusty homemade rolls to the delicious “amuse bouche” (it means “taste-teaser” in French) served at the beginning of each meal, to the tiny lemon tarts, chocolates and caramels presented with the check.

At lunch, we chose a chilled tomato consommé with stuffed summer vegetables ($12) , and a vegetable soup flavored with chervil and boasting a huge dollop of fresh Vermont cream that would have made Ben and Jerry jealous ($11). Both were bursting with intense flavors, although I wondered why the same appetizers cost $14 and $12, respectively, at dinner.

My guest ordered the roast rack of Colorado lamb, served with baby green vegetables and a stick-to-your-ribs white bean cassoulet, the traditional dish served for generations in French homes ($25). The medium rare lamb was cooked in its rich juices and attached to four giant ribs, and my guest pronounced it a dish fit for a king, or at least a hearty eater.

I had the seared filet of Atlantic salmon with vegetable confit, served atop an ethereal rosemary cream sauce ($19). It, too, was a generous portion, perfectly prepared.

We finished with coffee and two mouth-watering desserts: a rhubarb tart with strawberry marmalade and homemade vanilla ice cream ($10) and a caramelized beer brioche served with roasted pear and homemade beer ice cream — that’s right, beer ice cream ($12), which was better than it sounds.

When I returned for dinner with my wife several nights later, I encountered my only disappointment, food-wise. My rack of lamb proved a pale imitation of the luncheon version, both smaller and fattier, even though it was $7 more.

However, my wife raved about her appetizer, chilled light cream of Maine lobster soup, served with crunchy vegetables ($18), and her main course, a braised breast of guinea hen stuffed with fine herbs, and served with green peas and chanterelle mushrooms ($30). Fantastique.

She also raved about Maxime, our handsome young waiter, who told us in heavily accented French that he had only recently arrived from his hometown near Lyon, the gastronomic capital of France.

My sub-par lamb and glass of 1998 Chateau Greysac red Bordeaux wine that got lost enroute to our table were more than made up for by a sensational appetizer. A signature dish of Monsieur Westermann, it is sautéed frogs’ legs with Alsatian ravioli filled with onion compote, served with a chervil sauce ($19). The dozen frogs’ legs were sautéed in garlic and olive oil and arrayed on the plate like a miniature Maginot Line. It is a fantastic dish.

My wife chose to forego dessert but, in keeping with duty, I ordered the marinated fresh strawberries topped with a crunchy tuile and served with homemade verbena ice cream ($12). The surgically sliced berries encircled a strawberry mousse that was both beautiful to look at and wonderful to eat.

The restaurant has an extensive and reasonably priced wine list, representing top wines from California and France, including those from each of the Bordeaux regions and Burgundy. Wines by the glass are also available.

Clearly, Café 15 is here to stay, and has the potential to become one of Washington’s finest restaurants. I only hope that the service improves and that the prices, which Chef Piel told me are typical of a Michelin three-star restaurant, don’t go any higher.