IANAL.
from what I do understand, precedent sorta kind maybe a little bit matters, but courts can basically do whatever the heck they want, basing their decisions purely on the text of the statutes. They are specifically not bound by the interpretations of that law that they or any other court used in the past.
But the benchmark is the same: whether the judge's decision would stand an appeal.
From what I've read, civil law allows more than just a blind compliance with the law. Like in the case here: the reality of human interaction has changed, but the right to privacy is a basic one. While in USA you already think in precedents, quoting here copyright and first amendment, in Germany it is viewed simpler: we had privacy 50, 25 years ago, and technical progress should not disregard it. Instead it should accommodate it. While US courts are more or less obliged to think of the information the way it was 100 years ago - German courts are not and as such they are free to reinterpret the laws in a modern context, whatever past decisions might have been.
The craziness of USA legal system is that you had to have a case about garage door opener. For some time, garage owners were not sure they own the doors to their own garages. That's just crazy.
The craziness of Germany legal system is that judges might decide (and do) absolutely equivalents case, 100% perfectly matching, differently. But luckily that happens when modern reinterpretation of the law is still unsettled, like it happens right now with the copyright and privacy cases. But even if interpretation of the law is settled, judge might still take into the account personal human factors and decided differently.
Though, the German system isn't really crazy as it appeared to me first. Judges here meet periodically to discuss unusual decisions and to come to common interpretation of the law. Precedents might be not as important - but still it makes sense to save time and effort by relying on previous ruling. From what I heard, btw, majority of German judges do not really bother inventing their own decisions, relying mostly on the precedents. But still they take pride in making a unique decision when one is needed.
( Interesting side-effect of this is that German politicians occasionally pass a law which they deem important/urgent - without thinking through the consequences. They know they can rely on judges to decide the cases on the expressed intent of the law, instead of literal word-by-word interpretation. As soon as the law is field-tested, so to say, law is reviewed and amended to clarify and improve wording and close the loopholes. )
Again, IANAL. Most information I have is based on reading German newspapers, while still learning German. Take it with s grain of salt.