A late summer day in Florence, Italy, and the Piazza del Duomo is heaving. Tourists in shorts and T-shirts swig mineral water and squint up at the green-and-rose facade. Contessa Simonetta Brandolini d’Adda walks briskly through the throngs in a navy suit and matching slingbacks. Because of a phone call she made a few minutes before, the door at the Accademia Gallery will open—despite the fact that the museum is officially closed for the day—allowing the Contessa and her guests a private view of Michelangelo’s David.

A phone call from the Contessa is a powerful thing: It can get you a dinner with an Italian industrialist or a personal tour of the Vatican. But perhaps most important, it can help you obtain a slice of coveted real estate, like a Medici palazzo for a season. The Best in Italy, the real estate company Brandolini runs in Florence with her husband, Conte Girolamo Brandolini d’Adda, caters to the very discriminating—or at least the very rich—and frequently to the very famous, mainly from Great Britain and the United States.

The Brandolinis’ approach bucks the current internationalization of the real estate market. High-end real estate firms such as Sotheby’s International Realty, Savills, and Knight Frank—which opened a Florence office this past spring—increasingly cater to wealthy people around the world. “If you take your high-net-worth individuals, they don’t necessarily want to be in one country,” notes Knight Frank’s Bill Thomson. “What they really want is a lifestyle, and whether it’s in the South of France or Portofino or Venice, it doesn’t matter a whole lot.” Large, prestigious international firms are buying up smaller boutiques—or building partnernships with them—and are increasingly attracting listings from local sellers, who figure the international groups have a broader and more affluent clientele.

But the Brandolinis prefer to stay small and local. They offer not just houses, but entrees. “If someone needs, say, a palace in Milan or Palermo, you probably know who has one,” says the Contessa, describing her business. “Or if not, you know someone who knows someone.”

Like the European aristocrats in Henry James novels, Brandolini trades in connections, linking New World money with Old World nobility and property. Financier Felix Rohatyn, film mogul Paula Wagner, and ad supremo Charles Saatchi have all been clients of Brandolini’s. When Tom Cruise and Nicole Kidman were still married and sought a secluded Tuscan bolt-hole, the Contessa secured them the Villa Pisana, a stately 19th-century mansion discreetly tucked into a 7,400-acre estate outside Pisa. Sting, a longtime client of Brandolini’s, once brought along his mobile studio to record an album in his rental villa. Brandolini persuaded the owners—who weren’t quite sure what this blonde inglese actually did—not to balk at the trucks and hordes of technicians.