If it is truly an original, I would first have it appraised by someone knowledgeable and involved in art requisitions. In doing research online, I did not find any definitive answer, though a similar painting by de Vries sold at Sotheby's for 80-120 thousand dollars. The first step would be to determine if it was indeed an original painting. If there are no collectors who are interested, certainly an art museum would be willing to pay a generous amount for such a rare piece of artwork. Another option would be to hand it down through your generations as a family heirloom. Whatever you decide to do, I wish you good luck and hope you find a good home for it. It sounds like a great find!