I do not know of any misaligned incentives such as protectionist measures to impede imports or promote exports. And there is obviously no manipulation of the exchange rate to create current account surpluses in Germany; the euro is a free-floating currency. Of course, a current account surplus reflects a surplus of savings over investment.
To the extent that capital is flowing out of the country due to missed investment opportunities, public policy action is certainly called for. The way to go, then, is to create a more investment-friendly environment in Germany.