Jean Prouvé Rare demountable chair, model no. CB22, 1947
Two of these chairs were sold for $56,250 each at a NYC auction of Phillips in December 2012.
Another one of 1948 is for sale at Phillips in London next week.
Update: Where it was sold for £50,000….as the £ is a bit higher than the $, I would say the prices are moving up.