Via Terry Martin, I see that a Federal court in Ohio has rejected a claim by the heirs of Martha Nathan who were seeking to recover a Gauguin painting she sold in 1938 after fleeing Nazi Germany. He's posted the decision here.
UPDATE: More from Derek Fincham at his Illicit Cultural Property blog: "Whether the claimants will seek an appeal remains to be seen, but it seems likely given the value of the work. However, they do not have a great set of facts to work with here. Their ultimate success seems quite unlikely."