Authorities have combed through the main station of the former capital, according to local media. Railway traffic was diverted to a nearby station across the Rhine River.
German railway operator Deutsche Bahn on Sunday said the central station in Bonn was closed due to police investigations.
Local newspaper General-Anzeiger said the closure was due to a bomb threat. However, police did not locate a device after combing the station and the surrounding area.
About 60 state and federal police officers were deployed to the area, along with five sniffer dogs.
Trains were diverted to a nearby station in Beuel. Deutsche Bahn said would-be travelers should expect delays.