Heir says Cezanne watercolour in Basel show was lost due to Nazi persecution

A watercolor by Paul Cézanne (1888) shown at the Fondation Beyeler's recent exhibition once belonged to Gustav Schweitzer, a Jewish businessman who fled Berlin in 1935. Provenance researcher Willi Korte discovered documents in Basel's public archives showing Schweitzer loaned the work to the Kunsthalle Basel for a 1936 exhibition. Correspondence continued until 1939, when the work was returned to Schweitzer's secretary. How Schweitzer lost ownership remains unknown, but Korte says it was either sold under duress or looted in Nazi-occupied territory. The Fondation Beyeler has stated it will return the work to its current lender, an unnamed private collector based in the US.