Hans Olsen?
I have never seen this exact chair. The back of the chair is similar to a Hans Olsen design. Hopefully, that will help your search.
http://www.galleryshop.nl/index.php/16.php/111667.php
EBAY
Similar Wegner chair on Ebay
http://cgi.liveauctions.ebay.com/374-Hans-Wegner-Swivel-chair-model-50-J...
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