The German thin tank DIW downgraded its economic growth forecast for Germany on Wednesday. The economy is expected to expand at 1.5% in 2015, down from the previous forecast of 2.2%. The downward revision was driven by the weak industrial production at the beginning of the year.

The German economic growth in 2016 is expected to 1.9%.

"The German economy looks stronger at the moment than it actually is," DIW President Marcel Fratzscher said.

He also said that a Greek exit from the Eurozone is an "enormous" risk to corporate investment in Germany.