Why did the treaty of versailles make such harsh demands on Germany?

Germany was considered by the Allies in Europe as being responsible for causing the First World War.

Details:

The Treaty of Versailles, which came out of the Paris Peace Conference in 1919, was very punitive towards Germany. Germany was forced to admit responsibility for causing the Great War (World War I). We now call that "the war guilt" clause of the treaty. Germany also was forced to pay large reparation payments to the Allies (who opposed Germany in the war). Germany also had to give up large portions of its territory and lost colonial territories. And the German military had major restrictions imposed on it - - it had to be a volunteer military only, of no more than 100,000 men, and they could not have an air force.

All these measures were taken because it was thought Germany was too warlike and had brought the Great War upon Europe. However, the harshness of the terms actually set the stage for another World War, as Germany sought to reestablish its national pride.