Due to changing forms of crime, law enforcement agencies have had to adapt their methods. Undercover investigative activities by individuals, such as undercover agents or informants, have become indispensable in our current criminal proceedings. Against this background, the handling of such investigative personnel under German law is first presented, focusing on the legal foundations as well as the legal concerns and consequences of undercover investigations for the criminal process. In a second step, the situation under German law is compared with the legal situation according to the European Convention on Human Rights and the specific case law of the European Court of Human Rights. It is shown that German jurisprudence largely takes into account the requirements of the Strasbourg Court, although there are also significant divergences regarding certain procedures.