A bankrupt affiliate of Sotheby’s International is suing the attorney who handled a $17 million residential real estate deal in Fort Lauderdale, Fla.’s tony Harbor Beach area, saying he owes the brokerage more than half a million dollars.

Trustee Alan Goldberg, on behalf of SOL Sotheby’s as SOL LLC, claims Kurt Bosshardt kept $510,000, or half of the 6 percent commission allegedly owed Sotheby’s for the $17 million sale of 1 Isla Bahia last year.