German police said on Sunday they had ended a major operation launched after they received information about a possible threat of an attack in the south-western town of Offenburg on Saturday night.
Officers stepped up security in the town centre and on public transport and police said one possible target was a night club which was not named. Investigations were continuing but no further details on the nature of the threat were available.
A spokesman in Offenburg, in the state of Baden-Wuerttemberg and close to the French border, did not give any further details.
Germany is on high alert following deadly militant Islamist attacks in France and Belgium and after a failed asylum seeker from Tunisia drove a truck into a Berlin Christmas market in December, killing 12 people.
On Saturday, police in the city of Essen closed a shopping mall after security services warned of a possible attack.