The Hay-Adams, the conservatively elegant hotel of the rich and influential and a venerable Washington landmark overlooking Lafayette Square, is being sold to a French hotel developer for a reported $13 million to $15 million.

Georges F. Mosse, until recently general manager and part owner of three major Paris hotels and the famous Cafe de la Paix in Paris, said he is buying the Hay-Adams as the first in a chain of small, deluxe hotels throughout the United States that he hopes to acquire and refurbish in a unique French style.

"The Hay-Adams will be his flagship," said Walter Pozen, Washington attorney representing Mosse in the purchase. "He's staking everything he has on it."

The 170-room hotel at 16th and H streets NW is currently owned by Washington real estate developer Sheldon Magazine and his family. Mose said he signed a purchase contract with Magazine in March and expects to acquire the hotel at a formal settlement in mid-July.

The acquisition of the 52-year-old hotel, noted for its dark walnut-paneled lobby and old world personal services (complimentary bathrobes and personally engraved brandy sets for VIP gues's) contributes to the growing internationalization of Washington's downtown renewal.

Nearby Connecticut Avenue has blossomed with import shops, overseas airline offices and French and Italian restaurants. Tony boutiques specializing in continental items are replacing laundromats and dry cleaners. Law firms with international clients occupy renovated town houses around Dupont Circle. Pennsylvania Avenue just southeast of the Hay-Adams is about to undergo an architectural and economic rebirth.

The Hay-Adams, Mosse says, is thus ideally located at Lafayette Square -- securely anchored between the two great avenues and overlooking the White House.

Gesturing energetically during an interview and lapsing into French in occasional moments of frustration, Mosse also said he hopes to add to the Hay-Adams' present clientele a new influx of business and government officials from Europe - putting him in head-to-head competition with two other hotels that cater to foreign visitors here, the Madison and the Fairfax.

Neither Mosse nor members of the Magazine family would discuss details of the Hay-Adams purchase. Mosse said the sales price was somewhere "between $10 and $15 million." Another source said the figure was "near the top of that range."

The price is the highest ever paid in Washington "for an existing hotel," Pozen said.

Mosse. 37, an economist, author and private airplane pilot, was until recently general manager and part owner of the Cafe de la Paix in Paris as well as three hotels -- the Hotel Meurice, the Grand Hotel and the Prince of Wales (Prince de Galles) Hotel -- all well established hosterleries with a combined total of more than 1,000 rooms.

He said he decided some time ago to develop his own independent chain of hotels, sold his interest in the Paris businesses and "began looking for an opportunity here in the U.S."

"I traveled a great deal, looking," he said. He came to Washington last November and "visited all the major hotels in the city." He like Washington.

"I decided that if there was an opportunity, this was the first city to purchase a hotel in," he said.

Of all the possibilities, he liked the Hay-Adams best, Mosse said. He and Pozen approached Magazine, who indicated interest.

"We began serious negotiations in early March." Mosse said, "and on March 22, we signed a contract for purchase."

Sheldon Magazine, the current owner of the Hay-Adams, could not be reached for comment, but Marc Magazine, his son and the general manager of the hotel, said yesterday Mosse had approached the Magazine family through a friend in common, "and we hit it off just right."

He said the family had repeatedly resisted offers by others to buy the hotel since the Magazines acquired it in 1973. "Every week almost," he said, "it seemslike somebody's come in wanting to buy it -- an Arab, a rich Texan, you name it."

Said Magazine. "This has been a family operation since 1973. So we are glad to have it continue as a family operation with Mr. Mosse."

Mosse, who holds a PhD degree in economics from the University of Paris and wrote a 1973 book on international economics, has severed all ties with the Paris hotels. He now operates under the corporate name of Meurice International Hotels and is its sole owner. It is understood he plans to pay for the Hay-Adams with cash from his previous Paris business plus substantial loans.

Mosse said he will bring his wife, Danielle, and their two children to Washington in July to live permanently, and his wife will direct extensive renovations at the Hay-Adams.

Choosing his words carefully, Mosse described the present appearance of the hotel as "very charming American decor... but Washington needs to have a very old-fashioned hotel with a French style to it."

He said, "I don't want to get rid of the American style but I want -- how do you say? - to 'enhance' it with a French touch, a French elegance."

This will include, he said, putting flowers, more lighting and new funiture in the lobby and replacing the white paint in the hotel rooms with various wallpapers.

The Hay-Adams -- named after two homes formerly on the hotel site occupied by 19th century statesman John Hay and historian Henry Adams -- will retain its name, Mosse said, as will its sumptuous restaurant, the President Adams Room.

But the name of the hotel coffee shop -- the Preamble -- will have to go, Mosse said, a faint trace of disdain on his face. "Perhaps we will call it 'Relais Lafayette,' something French like that," he said. "Relais" means inn or coaching stop in French.

Renovations will take two to three years. Mosse said but will not require closing the hotel. He said he expects to raise room prices about 20 percent.

Current daily rates range from $59 to $85 for a single room, $72 to $98 for a double, and up to $250 for a suite.

The restaurant will feature French cuisine, Mosse said, and the hotel staff, virtually all of whom he says he intends to keep, will be retrained in a "French style" of service.

And the uniforms of the staff, the royal blue jackets and somber gray hats of the doormen? "Yes, the uniforms," muttered Mosse. "I think something will be done about them, too." $130" Picture 1, Hay-Adams lobby, above, with its conservative, traditional decor, will be refurbished.; Picture 2, Nattilay dressed doorman stands guard at the front entrance of the 52-year-old hotel, by Gerald Martineau -- The Washington Post; Picture 3, Georges F. Mosse discusses his plans for buying the Hay-Adams. Formal settlement is expected in mid-July. By Linda Wheeler -- The Washington Post