Do you believe there are any former Jewish possessions the Nazis stole, then murdered the rightful owners, and therefore should be returned to their rightful next-of-kin if they still exist? Would any Polish courts recognize the claim?
We have similar situations in the USA. There is a claim that old Spanish Royal land grants were violated and land the land was stolen by settlers. The Spanish heirs have made a claim in court which blocked all real estate transaction for the past two years.