The Daily Mail has further details on that Polish customs find that was authenticated this week as a very small Renoir measuring 7 x 9 inches and discovered in the post because Poland has a 25% tax on art works being exported:
Officials have established that it was sent from the small town of Konstancin-Jeziorna, 20km south of Warsaw, and that it was not stolen. ‘We have been unable to find the person who posted this canvas and we have had no response to our inquiries about the post office box in America,’ said regional prosecutor Pawel Wierzcholowski. ‘If this continues the painting will go to our museums and antiquities department.’.