Warning: My German legalese isn't very good and this is not legal advice. I unfortunately know very little about how the German court system works and where to look up stuff.

The law[1] is worded like this:

> (1) Mit einer Funkanlage (§ 3 Absatz 1 Nummer 1 des Funkanlagengesetzes) dürfen nur solche Nachrichten abgehört oder in vergleichbarer Weise zur Kenntnis genommen werden, die für den Betreiber der Funkanlage, für Funkamateure im Sinne des § 2 Nummer 1 des Amateurfunkgesetzes, für die Allgemeinheit oder für einen unbestimmten Personenkreis bestimmt sind.

The law basically says that you may only listen to (or take note of in comparable way[2]) messages that are:

1. For you, the operator

2. For amateur radio operators according to the Amateurfunkgesetz

3. For the general public

4. For an indeterminate group of persons (I think that's an accurate translation?)

For me, a big question regarding aviation and marine traffic monitoring is what "unbestimmten Personenkreis"/"indeterminate group of persons" actually means. Since "die Allgemeinheit"/"the general public" is listed separately, I'd assume it's a distinct group from that, and to me the previous commenter's "meant for any member of the public who happens to be flying a plane nearby" sounds like it could fit that description. I'd argue, for example, that police radio is for a "determinate" group of persons, police officers and dispatchers working for the government, whereas aviation and maritime traffic is an "indeterminate" group of people, people working for all sorts of airlines, shipping companies, recreational pilots/boaters, who happen to be around the same area.

If anyone has any links to cases where this law was tried in relation to aviation or maritime communications, please share them, I have been struggling to figure out where to look for this stuff, on top of that, the law was also renamed or moved around, which makes it extra confusing.

[1] https://dejure.org/gesetze/TDDDG/5.html

[2] Might be related to this weird ruling, where a judge in a case about some ADS-B receiver decided that it was ok because rendering the position of aircraft wasn't "listening to" (as in, literally hearing) the traffic: https://openjur.de/u/130555.html - This decision is probably moot now, due the addition of "take note of in comparable way". The judge briefly mentions that actually listening to the traffic could be violating the law, but I am not sure if this point was ever properly litigated.