Talk politics.

I assumed Germany only wanted trade expansion and a sphere of influence in central Europe. They weren't after any territorial expansion per se, although the treaty they signed with later with the Soviets (to get Russia out of the war), gained them huge swaths of land in Poland, and the Ukraine-- all of that would have not happened had the war ended quickly with another defeat of the French. I'm not sure about what the other aims were for the other combatants.