git revert -m 1 <merge-commit>
With ‘-m 1’ we tell git to revert to the first parent of the mergecommit on the master branch. -m 2 would specify to revert to the first parent on the develop branch where the merge came from initially
(lieber vorher prüfen welcher branch welcher ist)
ref~ is shorthand for ref~1 and means the commit's first parent. ref~2 means the commit's first parent's first parent. ref~3 means the commit's first parent's first parent's first parent. And so on.
ref^ is shorthand for ref^1 and means the commit's first parent. But where the two differ is that ref^2 means the commit's second parent (remember, commits can have two parents when they are a merge).