German law allows predatory lawyers to file lawsuits on behalf of another party without their involvement. That level of BS thankfully doesn't happen in the US.
Abmahnung is not a proper lawsuit, it's a mostly legal way to get parties to agree in case of a legal dispute without having to actually involve a court. You can ask to be reimbursed for incurred costs for up to 1000€. The current government is working no reducing the abuse of this legal mechanism.
Sending one of these requires you also to clearly show how the recipient infringed on your rights or a law that affects you or your business in a negative way and lay out the costs you want reimbursed for sending the letter (up to 1000€). If you're wrong about it you'll have to pay all and any attorney fees of the other party.
If someone refuses to pay or sign the Abmahnung you have to go to court, in which case you'll need agreement from the party you're representing.
To file an actual lawsuit you still need to be wronged or damaged by the actions of another party, you can't just sue in the name of someone else without them agreeing to it. This is also limited to civil law, criminal law is handled by the state prosecutor via the police, not you yourself.
- If you are found wrong, you have to pay the defending party legal costs;
- If the defending party ever decides to fight and you don't have the approval of the wronged party, you can't even defend yourself (read the point above again);
- It's only for small values, and there is no upwards negotiation (you must lay the costs down at the letter).
That's the government not requiring a judicial process for small values, while keeping all the rights of the defending party (I wish my country had something like that). You may not care about the difference, but that only speaks about you, because there's a huge difference there.
I take semantical distinctions that are very important because those are important in the law because law isn't made by people that don't care about it for 300$.