A sense of luxury is apparent from the moment you step into Mass Court, a new 14-story apartment complex at 300 Massachusetts Ave. NW, on the edge of Chinatown and Judiciary Square.

There is 24-hour concierge service and a guard on duty around the clock. The lobby features beige marble pillars, plush upholstered tan and chocolate-colored chairs and sofas, and a working fireplace.

Down the hall is a business center that feels like a high-tech law library. The room has a dark, polished hardwood floor, bookshelves stocked with encyclopedias and law books, and three high-end computers with high-speed Internet access, a fax machine and a printer.

That's just the beginning.

Around the corner is an indoor fitness center with treadmills, free weights and sophisticated exercise equipment. There are rooftop decks with a running track, a pool and dramatic views of the Capitol.

Next door to the fitness center is a spacious party room, complete with a full kitchen and a huge plasma-screen TV. Tenants can rent the room for parties and receptions.

Mass Court is a combination of new and old. The main building, of red and tan brick, is new. The computers, exercise machines and kitchen equipment in the common areas are state-of-the-art. Mass Court also includes a three-story "historic building," constructed in 1890. That building has seven units.

Mass Court has a variety of floor plans, including lofts that are available in studio, one-bedroom and two-bedroom sizes.

The complex's tenants are surrounded by dozens of entertainment, dining and transportation options, all within walking distance.

Union Station, with its movie theaters, shops and restaurants, is about four blocks away. The National Building Museum is around the corner. Chinatown, the MCI Center, the Spy Museum and the new Convention Center are all within 10 minutes by foot. Capitol Hill and the Mall are about a 15 minute walk away. Several Metro and bus lines are within a short walk.

Many of the tenants who began moving into Mass Court in March were drawn to the complex as much by its location as by the luxury.

Tim Davis, a Marine, was the first tenant to move into the building, in mid-March.

Davis had been living in downtown San Diego after serving in Iraq. After doing well on the Foreign Service exam last year, he needed to find a place to live in the Washington area to attend Foreign Service school in Arlington, he said.

While still in San Diego, Davis, 35, began surfing the Internet, checking out Web sites of Washington area apartments. Davis said he decided to move into Mass Court after viewing its Web site.

"I knew about places like Adams Morgan and Georgetown. I would prefer to be part of a developing downtown community rather than an established one," Davis said. "I like it a lot here, like the urban feel. I can walk to the MCI Center in five minutes. I can walk to [the] Spy Museum or the Shakespeare Theater." He takes Metro to school in Arlington.

Mass Court is managed by Trammel Crow Residential Services. Davis and other tenants raved about the management company.

When his girlfriend came from California to visit him on short notice, Davis said, he was unable to pick her up or meet her at his one-bedroom apartment. A member of the management staff met his girlfriend at the complex, greeted her by name and let her into his unit, Davis said.

"They went way out of their way. They even left me a fruit basket" Davis said.

Like Davis, Tom Quinn, 26, and his girlfriend, Susie Perez, 28, wanted to find a place downtown when they were apartment hunting last December.

They had another requirement that Mass Court satisfied: They wanted a place that allows dogs. Mass Court permits pets but does have a weight limit.

Quinn and Perez, both Hill staffers, were living in a nearby building that didn't allow dogs.

"We liked the neighborhood and wanted to stay in it," Quinn said. "We took a tour and didn't look at another apartment. We fell in love with the building that day. Everything was brand new and very well put together. We put our security deposit down that day."

Quinn and Perez moved into a one-bedroom unit in Mass Court in mid-March and are now the owners of a Boston terrier named Stitch.

"This building's definitely for dog lovers," Quinn said. "It doesn't take long to put the leash on and walk Stitch to the Mall or some of the small parks nearby on Capitol Hill."

Living in Mass Court is also for lovers of urban living, Quinn said.

"It's great. The Metro is right there, Chinatown, the MCI Center, anything you want is walking distance," Quinn said. "We've tried a bunch of different restaurants since we moved in. "

Urban life attracted Barbee Barber to Mass Court. Barber, 52, had been living at an apartment complex in Ballston before she moved into a studio in Mass Court in April.

"I love city life. Although Ballston was great, it was like being teased," said Barber, who works for the Smithsonian.

"Now that I live here, I walk six blocks to work. I often go home for lunch," she said. "I run errands between home and work, and lose no time whatsoever."

Because she is so close to work and to public transportation, she sold her car, saving money on insurance, gasoline and maintenance.

"Since I've moved here, I've gone to a lot of book readings, some Smithsonian events," Barber said. "I absolutely adore it."

Susan Casper, Elliot Anenberg and Isaac Metthias sit beside the rooftop pool at Mass Court.