The New York Times spoke to attorney Joel Lever and wealth consultant Peter May about the due diligence necessary when buying art:

“It’s important to generally talk about protecting what a buyer should do,” Mr. Lever said. “There is an arrogance of the buyer, often my client, and the seller, a well-known auction house, that exposes them to risks that they would not take with any other asset class.” […]

“Most people think of fraudulent transactions,” Mr. May said. “But you also have normal business issues, or it’s personal property of your balance sheet and you’re about to be sued.

Avoid Legal Pitfalls When Buying Art (New York Times)