The case concerns an incident at the spa pool in Bavaria's Berchtesgaden, just over the border from the state of Salzburg, where the Austrian claims he was overcharged a decade ago.
The pool had offered a third off the entry cost for visitors from five German municipalities that the pool served. Coming from Austria, however, the man was told that he would have to pay the normal price - an extra €2.50.
Ten years on, the crusading Österreicher took his case all the way to Germany's Federal Constitutional Court - the highest constitutional court in the country - arguing that he should have been treated equally.
Now the highest court has ruled in his favour, arguing that the rejection of his claim by lower courts could not be comprehended from “any perspective”.
In a statement released on Tuesday, the court said that although a business can favour locals, they need a good reason to do so.
As the pool tried to attract visitors from far away they did not have the right to exclude the Austrian from the discount deal, the court ruling stated.