The nonprofit Carnegie Hall Corp, which manages the 134-year-old venue, said Efstathios Antonakopoulos has "taken every opportunity" to trade off its image and brand to promote his Carnegie Diners in Manhattan; Secaucus, New Jersey; and Vienna, Virginia, with a stated goal to franchise nationwide by 2029.

Carnegie Hall objected to the restaurants featuring wall-size murals of its building and stage, selling T-shirts and other merchandise referencing the venue and referring to historic events such as appearances by singer Bob Dylan, soprano Maria Callas and civil rights leader Martin Luther King.

The complaint filed on Tuesday in Manhattan federal court said this is confusing customers into believing Carnegie Hall and Carnegie Diners were connected, and that years of trying to resolve the matter amicably have been unsuccessful.

It also quoted Antonakopoulos, who is known as Stathis, describing Carnegie Diner as paying "homage" to Carnegie Hall and people who appeared at the midtown Manhattan venue. One of the restaurants is located diagonally across the street.

"This is no 'homage'; it is theft," the complaint said.

Antonakopoulos and his company, Carnegie Hospitality, did not immediately respond to requests for comment. He became chief executive in 2019, according to the company's website.

Carnegie Hall said in a statement: "We filed the suit to protect both Carnegie Hall's intellectual property rights and innocent consumers who are likely to mistakenly believe that the restaurants are related to Carnegie Hall."

The lawsuit seeks unspecified damages, a halt to further alleged infringements, and the cancellation of Carnegie Hospitality's registration with the U.S. Patent and Trademark Office for Carnegie Diner & Cafe restaurants.

The case is Carnegie Hall Corp v Carnegie Hospitality LLC et al, U.S. District Court, Southern District of New York, No. 25-04224.