The relationship is, of course, pretty remarkable now. It is less than one hundred years since WW2 and Germans can live in harmony with say, the English.
How long did it take to get to this point? Was it pretty much instant after the toppling of the Nazis? Was it quick because everybody, no matter which side you fought on, was in the same boat (i.e. you were pretty much made to fight to your government?)
The mending of bridges between West Germany and its neighbours was remarkably swift, its difficult to pinpoint an exact time-scale, but there are definite events that can be argued to demonstrate a lessening of tensions between the two.
In 1945 as we know Germany was split into the four zones of occupation. Initially the allies and the USSR were somewhat at odds with how to govern the occupied Germany. France and the Soviet Union were heavily in favour of extracting reparations in kind. Charles Monnet, a French Civil Servant, proposed in a memoranda written on september 8th, 1945, that among other things, France would detach the coal rich areas of west-germany in the Saar and the Ruhr to help reconstruct France. The Saar was detached, and the protectorate of the Saar was established, the French were not allowed to seize the Ruhr however, instead the International Authority for the Ruhr was established in 1949, as a pre-condition for the creation of the Federal German Republic, (and the ending of the western occupation zones in Germany).
The three Benelux countries all submitted requests to annex German territory, Luxembourg was not allowed to by the Allied Control council, Belgium's request was eventually approved, but in 1949 the government of Belgium declined the opportunity. The Netherlands did annex some German territory, but chose to return it in the 60s, when the German Federal Republic paid reparations.
The main turning point, was the creation of the European Coal and Steel Community in 1951, which was signed between France, Germany, Italy and the Benelux countries. The treaty is generally held as the original basis of the European Union, it consisted of a promise by the signatory countries to support each other in their production of Coal and Steel, agreeing to supply each other when necessary, and to not levy any tariffs on cross border trade.