If the Germans wanted to help defuse potential problems from France later, they could have given the "rump Walloon" territory (after the Dutch annexed Flanders) to France as a kind of consolation prize.
After all, the Congress of Vienna did not turn into "everybody rape France" even though Napoleon took longer to defeat at a higher cost than the French did in TTL.
True, but as we've seen before in history mercy rarely enters the victor's thinking. Territorial greed, however, does. Also, I wanna spice things up .