There is no provision in the German Code of Criminal Procedure (Strafprozessordnung) that requires the recording of the interrogation of a suspect or a witness and there seems to be no movement either officially within the jurisdiction or within the legal profession to require that.
Apart from the fact that the criminal procedure in Germany is inquisitorial and the method of gathering evidence is therefore different from that in the adversarial system, the need to record interrogations might be regarded as a low priority due to the fact that in Germany a suspect is usually accompanied by a defence counsel during the interview. That minimises the risk of police impropriety.