The police officers rushed to the incident in Kaiserstrasse to assess the situation. Cordons were set up to protect the public, with members of the raid squad armed with heavy weapons. A police spokesman confirmed that “shots were allegedly heard” by onlookers.
The spokesman said the operation has been in place since 1pm local time.
According to social media reports, the incident took place near the station distract.
One person wrote: “Avoid the station district in #Frankfurt! She @FRlokal reports gunshots there in the city center.”
Shortly before 3pm local time, police said they had called a halt to the operation.
They said the alleged gunshot noises were actually stones that a stranger had thrown at the windows.
The person was provisionally arrested.
In January a mass evacuation took place at Frankfurt International airport after a suitcase was reportedly left by a man at passport control who shouted “Allahu Akbar”.
The 38-year-old man, from Slovenia, acted aggressively towards police at Frankfurt International Airport when police approached him for not wearing a face mask.
The man shouted, “I will kill you all, Allahu Akbar”, before he abandoned his luggage and attempted to flee the scene.
In response, Terminal 1 was evacuated and armed officers surrounded the suspect.
A spokesman for the federal police said the man left a bag in the terminal and then fled.
A Federal Police Directorate Frankfurt Main Airport spokesman said: “A federal police patrol approached a Slovenian man who was not wearing mouth and nose protection.
“He immediately showed aggressive behavior towards the officers and said, ‘I will kill you all, Allahu Akbar’.
“Due to his…behavior, the forces deployed assumed that his statement was serious.
“The man then tried to flee, but was immediately overwhelmed by the emergency services under threat of a firearm.”
Additional reporting by Monika Pallenberg