First it was gambling, and now Manhattan art dealer Helly Nahmad is being “sued for allegedly hiding a $20 million painting stolen by the Nazis,” according to the New York Post.

The painting in question is Amedeo Modigliani’s “Seated Man with a Cane” (1918), and the question of ownership over this modern masterpiece has been going on for years. Back in 2012, Philippe Maestracci, who is an Italian citizen living in Monaco, says the painting belonged to his Jewish grandfather who fled Paris when the Nazis invaded in 1939.

The Nahmad family said that the case was unfounded because New York’s Helly Nahmad Gallery does not own the work since the International Art Center does. But what is this IAC, you ask? Back in 2012, the Manhattan-based Gallerist art blog reported that IAC was an entity owned by David Nahmad and holds an estimated $3 billion to $4 billion worth of art in Geneva, Switzerland.

Now Maestracci is suing two Nahmads, Helly and his dad, David Nahmad, to find out who owns the “murky corporation” and who actually owns the painting.

It should be noted that earlier this year the Maestracci v. Nahmad art restitution case was voted by the The Richest website as #4 in their five most controversial legal battles over art.

This blue-chip art story checks all the boxes: Monaco (where most art summers), Manhattan (where most art is sold), Switzerland (where most art is stored), Modern Masters (what most art people want), Nazis (the villains of modern art), the 1% (ok, the 0.01%), and, the best part, a murky corporation (which will own everything one day).

Hrag Vartanian is editor-in-chief and co-founder of Hyperallergic.