Historians are divided on the question of what the German government was planning before World War I began, but German war aims were spelled out very clearly soon after the start of the war in the so-called "September Program" of German chancellor Bethmann-Hollweg. These aims included the annexation of territory in France, German economic and political domination of central Europe, and the creation of a German colonial empire.
Germany and France had been rivals for decades at the onset of World War I. The first German war goal was to cripple French military and economic power for at least a generation while annexing regions of France with arms-producing capabilities. In Bethmann-Hollweg's memorandum of September 9, 1914, he listed Germany's first war aim as the annexation of the iron-producing Briey region of France along with other areas. France would also be forced to pay a large indemnity designed to make any large-scale military buildup impossible, and to sign a treaty giving Germany economic domination of French markets.
Build an Empire in Europe
Along with weakening the power of France, Bethmann-Hollweg also wanted to annex land from Belgium and turn it into a vassal of the German empire. Luxembourg was to receive some of the land annexed from Belgium while becoming a part of Germany. Holland was to remain nominally independent under German influence. Germany would also establish an economic alliance or "customs union" called Mitteleuropa that would give it a dominant position over the economies of all member nations.
Become a Colonial Power
Germany and its ally Austria-Hungary were both powerful in Central Europe at the beginning of the war, but neither possessed a colonial empire on the scale of their British or French enemies. While the "September Program" of 1914 states that the issue of German colonies in Africa would be addressed at a later date, Bethmann-Hollweg used the phrase "the creation of a contiguous central African colonial empire" to describe one of the options that would become available to Germany if it won the war.
Blueprint or Daydream
Although Bethmann-Hollweg's September Program describes a clear set of openly expansionist war goals, it is unclear whether any of these goals had existed before the war began. The September Program could be evidence that imperial Germany planned and caused the war deliberately in an attempt to become the dominant power in Europe. However, another possibility is that Germany drifted into the war unintentionally and the sweeping war goals Germany adopted after the war began were a reflection of excessive optimism rather than a blueprint.