There are a lot of institutions concerning child protection issues. Please consult any age group of the federal state you live in, there you will find an address you can contact. If you want to contact someone in person, please contact the kindergarten, the school or the office for youth welfare. It is extremely important that you consult an expert to report your observations or your knowledge about the issue. It is problematic to accuse someone directly yourself, because that will possibly lead to a conflict you might not be able to solve. The experts will help you how to find the best way to protect the child. If there is an immediate danger for the child, do not hesitate to call the police!
Please consult the Convention on children’s rights to learn more about this topic. That makes it a lot easier to know when and how you should intervene to protect children.
You can find information concerning child protection in Germany here:
The UN-Charta on children rights can be found here: