Going into the conflict what were they hoping to achieve, and near the end if the Michael offensive was succesful and the allies sued for peace, what could have/would have the Germans gone for?
This was actually a pretty controversial subject for a lot of people because the Fischer Thesis tackles this directly -- and Fischer happened to be a German historian. He published in 1961 a book titled "Griff nach der Weltmacht: Die Kriegzielpolitik des kaiserlichen Deutschland 1914–1918" which was published in English as ""Germany's Aims in the First World War." His thesis was based off of documents which were recently released, notably the Septemberprogramme, or "September Program" which was a document drafted by the German government in September 1914 which described what their demands would be in event of victory.
They were, by all accounts, extremely aggressive and it shocked a world at the time which saw the First World War not as a war of German aggression but Germany's response to her neighbors aggression. Fischer, a German at that, would use this document as his prized horse to make the conclusion that the First World War was started by Germany under the pretense of the assassination in Sarajevo for expansionist gains. Such an accusational stance isn't taken as seriously this day (many people, including me, disagree with the overall Fischer Thesis because its conclusion. That being, Germany starting a war based on war goals it drafted AFTER the war started doesn't fly) but the document it's based off of is certainly legitimate. The pendulum is in his thesis' direction while the literal thesis itself is rejected I guess is what I'm saying.
You can actually read it here for the German speakers. The spark notes, for you non-German speakers, are this:
All fortifications from Dunkirk to Boulogne will be destroyed.
The ore rich area of Briey will be annexed outright. Coastal strips in the North would also fall under German control.
War debts shall be imposed on France so large that she is incapable of rearming herself for 15-20 years
The French will cease all trade with Great Britain and will be reliant on the Germans economically.
Either the outright annexation of Belgium or the seizure of lands up to Antwerp and making the rest a "vassal state"
Luxemburg integrated into the empire as a "Germanic State" (think how Prussia, Bavaria, Wurttemburg, and Saxony were quasi-independent states in the Empire)
The creation of a Central European economic sphere (think EU almost) of the German client states in the West and the newly formed states created in the East from a supposed Russian defeat as well. All client/buffer states of Germany, of course. Translated it states " including France, Belgium, Holland, Denmark, Austria-Hungary, Poland and tolls. Italy, Sweden and Norway. This association will not have no common constitutional supreme superficial equality of its members, but actually under German leadership, must the economic dominance over Central Europe stabilize. "
The annexation of all Central African colonies controlled by Belgium and France -- basically creating a continuous state across the continent.
This is, in essence, calling for a European empire with Germany at the head and a seizure of large swathes of Africa (Germany's "place in the sun"). This was, as I said, very controversial because in a world still recovering from the Second World War many, especially Germans, ESPECIALLY the Germans, saw too close of a correlation between that and the Nazi's just 20 years prior to this books publishing. There was as you imagine quite a lot of emotional backlash.
Now, there is no such document describing the war goals for Russia but we don't need one -- because the Germans beat the Russians and signed a favorable treaty. It's called the Treaty of Brest-Litovsk. Here is a map of the territorial gain of Germany.. A more in depth map. The Ukraine would be declared an independent state (but basically under Germany's thumb as a buffer state), Germany would gain control of the Baltics, the Russians would pay billions in gold marks. This treaty in many ways conforms to the goals stated above by Germany as they are basically in the same wheelhouse of the stated goals.
This treaty would also be cited as an example to refute those who cried out against the harshness of the Treaty of Versailles. If you didn't want Versailles you shouldn't have done Brest-Litovsk was basically the line of reasoning at the time.
Franz Fischer's English version of the book is available on Amazon. I can't link it because spam filter but it is titled "Germany's Aims in the First World War". Also basing analysis off of the Septemberprogramme document which is linked above.
