The Commission stated that the Sprengel Museum's own records showed clearly that Marsh Landscape With Red Windmill, a 1922 watercolour by Karl Schmidt-Rottluff, had belonged to Max Ruedenberg who had been forced to sell it in 1939.
It had been acquired in the same year by Bernhard Sprengel and recorded by his wife Margrit as having been previously owned by the Ruedenberg family, with whom the Sprengels were acquainted.
Max Ruedenberg was, like the Sprengels, a collector, businessman and member of the Hanover Kestner Gesellschaft, dedicated to the promotion of contemporary art and artists in Germany.
He and his wife were deported to Theresienstadt in 1942 where they perished.
The claim by their elderly grandchildren was first submitted in February 2012, but the Museum denied the evidence of its own documents and stated there was no proof of the painting's ownership by Max Ruedenberg.
To read the recommendation, only available in German, click here.