In June 2016, Bill G. B. Pallot and Charles Hooreman, rival antiques dealers in Paris, became the two most famous men in the French art world. That was when Pallot admitted to the police that he had masterminded the forgery of at least four chairs purportedly built in the 18th century for France’s royal household and, in a series of transactions via third parties between 2009 and 2015, sold them to the Palace of Versailles. For decades, Pallot, who ran the furniture division of the Parisian gallery Didier Aaron, had enjoyed a reputation as the world’s leading expert on the works of 18th-century France; indeed, Versailles’s decision to purchase the chairs hinged on Pallot’s blessing. And based on Pallot’s imprimatur, the government classified two of his fake lots as national treasures.

It was Hooreman who realized the chairs were new constructions, initially because he recognized in them the handiwork of Pallot’s gilder and carver. “I often use the same people on restorations, and I’m intimate with their strengths and weaknesses,” Hooreman says. He knew that one of them, for example, was fond of painting a coat of melted-down licorice on the surface of reproductions, to make new wood look old and dirty. In 2012, Hooreman saw a pair of ployants—folding benches—that were for sale in the Aaron gallery showroom and were billed as the onetime property of Princess Louise Élisabeth, the eldest daughter of King Louis XV, and acted on a hunch. “I licked the chair and voilà,” he says. “I could taste the fraud.”

The following week, he confronted Pallot, who had once been his art-history professor at the Sorbonne. “I told Bill he’d always been my hero and this wasn’t right,” Hooreman recalls. “He said, ‘I’m the connoisseur,’ and admitted nothing.” A few months later, Hooreman learned that Versailles had bought the ployants. He sent an e-mail enumerating his misgivings to the museum’s curators, under the subject heading “Acquisition Dangereuse.” They responded by forwarding his note . . . to Bill Pallot, whose gallery promptly threatened Hooreman with a lawsuit. Meanwhile, the pieces went on display, and were part of a major exhibition in 2014.

The French police were eventually moved to take up the case, and Pallot was arrested in 2016, along with six other alleged participants in his scheme. He served four months in jail on a preliminary sentence—he is awaiting trial later this year on a full set of charges (including fraud, money-laundering, and tax evasion) that could send him back—and officials suspect he may be responsible for other copies that currently reside in museums and collections around the world. Pallot says he is not, but Hooreman has remained on his trail, attempting to document his forgeries in an effort that the police acknowledge has served as a blueprint for their ongoing investigation. To date, Hooreman’s list contains 15 lots he considers fakes.

The case has gripped certain segments of a nation for whom patrimoine, royal objects, and state-run museums possess a measure of public importance not quite fathomable in the U.S. “Versailles is one of France’s great institutions, and for some Pallot’s crime is a fraud against the national identity,” says Harry Bellet, Le Monde’s reporter on the case. The notion of extremely wealthy collectors being taken advantage of is nearly as titillating: in Paris Match, Pallot was called “the Bernard Madoff of art.” William Iselin, a London antiques dealer who, in light of Pallot’s arrest, has launched a forensic effort to determine the authenticity of several world-class collections, told me that a number of his peers have long had a reputation for selling fakes, “but this stuff typically hasn’t come to court, because when rich people discover they’ve been had, they’re too embarrassed to come forward.”

“I told Bill he’d always been my hero and this wasn’t right,” says Charles Hooreman.

The news from Versailles has sent the multi-billion-dollar market for French antique furniture into a tailspin. The proprietors of Paris’s storied Galerie Kraemer, one of the houses through which Pallot’s ring allegedly sold fakes, have received court protection to structure a limited reimbursement plan for former clients, and face indictments and lawsuits from several collectors, including one over a pair of allegedly fraudulent cabinets it sold for more than $6 million. (Kraemer maintains its innocence in the Versailles-related case and claims to have been Pallot’s unknowing victim.) A number of American collectors who purchased furniture through Pallot or Kraemer over the years flew expert restorers to their homes from Paris last year to try to determine whether they owned forgeries.