Frankfurt is in contention for becoming the first trading center for China's currency in the EURO area. But the rivals never rest. The chances for Frankfurt increase. Perhaps the agreement of such an "offshore center" at the end of March will be agreed during the visit of the Chinese party and state chiefs Xi Jinping in Germany. It is Xi's first trip to the Federal Republic since he has taken the lead in the second largest economy in the world a year ago. The German financial center would benefi…