body: Our team is going to host a new web application with user generated content. We are wary of a scenario where a user uploads copyrighted material and the copyright owner comes after us. We are located in Germany and define a German court as the relevant jurisdiction in the TOS, the application has international audience. 
  
  
  We found information on how to react in the case of a proper Abmahnung (a German copyright complaint) which conforms to the requirements of German Urheberrecht (copyright law): <https://irights.info/artikel/abmahnung-grundregeln-richtig-verhalten-fristverlaengerung-unterlassungserklaerung/26088>. But we can imagine getting either a free-form copyright complaint or one according to some other law (e.g. a DMCA notice). 
  
  
  Are we expected to react to a non-conforming copyright request? Do the same rules work as for the standard Abmahnung, or is there some other procedure? Or can we ignore anything which does not fulfill the legal requirements of an Abmahnung? Also, if there is some definition of what a valid Abmahnung should contain, where do we find that definition? 
  
  
  Our application will contain scientific material, and the copyright holders will be mostly scientific publishers who have the staff to write a proper Abmahnung. But there are also people who self-publish articles or books and they could try writing one on their own. We don't want to be found guilty of neglecting a valid complaint just because it looked amateurish, but also don't want to massively remove legit content because of someone's claims. 
  
  
  
title: How to react to a non-formal copyright complaint in Germany?