I´m afraid to disturb your view of the world, but the ca. 5 billion US $ exports from Germany to Iran in 2006 are far from being 1% of Germany´s exports. The problem is not Germany, the problem are the UN veto powers China and Russia.
Russia and China’s veto power does not affect the unilateral decisions of Germany. They can enact their own sactions against Iran as the U.S. has done. They could even push for meaningful sactions from the E.U. The Germans are unwilling to pass on this market even though Iran is a state sponsor of terror and has terrorist proxies that actively wage war on Germany’s allies.