Brand told the BBC the discovery was “stunning”, describing it as “the most bizarre case of my entire career”.
“I have recovered Nazi-looted art from World War Two before, including pieces in the Louvre, the Dutch Royal Collection, and numerous museums,” he said.
“But discovering a painting from the famous Goudstikker collection, in the possession of the heirs of a notorious and famous Dutch Waffen-SS general, truly tops everything.”
He added: “For decades, the family, who of course bear no personal guilt for Seyffardt’s own crimes, had the opportunity to do the right thing and return this painting. They chose not to.”
This discovery draws parallels to a previous case where an Italian master painting stolen from the Goudstikker collection by the Nazis appeared on the website of an estate agent selling a house in Argentina.
A photo showed the portrait of a Lady by Giuseppe Ghislandi hanging above a sofa inside a property near Buenos Aires, once owned by a senior Nazi official who moved to South America after the Second World War.
The discovery led to a police raid on the property, but the painting had seemingly been taken down and moved by the time authorities arrived.