Dorotheum, from Austria, sells on 19 December 2016 a "Flemish School, 16th century" Virgin and Child in a landscape, estimated at 6,000 to 8,000 Euro.
Alberti's Window. The copy for sale is of course simplified and not by Dürer, but it is an interesting work nevertheless, and not very common. It may be Flemish, since Dürer was very popylar in 16th century Flanders, but with copies it is hard to be certain. The blog post mentioned that Jan Brueghel made a painted copy of the watercolour, but from both the description and looking at the quality of the copy for sale, it is unlikely that they are the same (the one for sale is clearly simplified).
The estimate seems a bit too high now that it has become clear that this is a copy; but as it is an old copy, and apparently a rather rare one, and not without charm, it should still be worth about 3,000 Euro.
UPDATE: not sold, as expected.