[kuerbel]

They don't have to follow it but leading decisions (Grundsatzentscheidungen) still influence how a lower court judge might interpret the same law. Based on providing legal certainty instead of stare decisis though. It's not a must, more of an... aid

[isaacfrond]

This is not such a decision though; it's a first instance decision at a lower court.

[9dev]

Still - a judge on another case will probably factor this one into their decision, but if they have a radically different view or the case is sufficiently different, they could just as well come to a different conclusion.