Well, this case was finally settled. Back in 2000, the heirs of Lilly Cassirer sued Madrid’s Thyssen-Bornemisza Collection, over Pissarro’s Rue Saint-Honoré, dans l’après-midi. Effet de pluie (1897). The painting was taken by the Nazi’s in 1939, and in 1976 Baron Hans-Heinrich Thyssen-Bornemisza purchased it from the Hahn Gallery in New York City.
After a 20 year battle, a California appeals court ruled that while the work was stolen … Spain did not know about the pre-WWII origins of the painting when they purchased the work from Thyssen-Bornemisza, and that he did not know about its origins when he bought the work in 1976. Because the museum did its due-dilligence prior to the purchase, the painting will remain with the Thyssen-Bornemisza, where it has been on display since the museum opened in 1992.