The confusion arose after two pairs of officers went to the jewellery shop in the early hours of Sunday when a passer-by reported robbers moving around inside, Berlin police said in a statement on Monday.
The plain clothes pair went around the back of the building to investigate – unbeknownst to their uniformed colleagues arriving at the front.
They in turn heard noise from the back of the shop, drew their weapons and shouted for the robbers to come out with their hands up.
One of the plain clothes officers ran around to the front of the building, gun in hand, to help with the arrest – and found himself under fire from his colleagues who thought he was a robber.
Once the Keystone-esque mix-up had been clarified – and it was established that no-one had been hit – the police officers went upstairs together and arrested a suspect.