The German Institute for Economic Research (German: Deutsches Institut für Wirtschaftsforschung, or DIW Berlin) is one of the leading economic research institutes in Germany. It is an independent, non-profit academic institution which is involved in basic research and policy advice. DIW Berlin was originally founded in 1925 as Institute for Business Cycle Research and was later renamed to its current name.
More information on the Wikipedia page 
The website, in German, is