According to the German newspaper Bild this operation was linked to an alleged fight between two men at a nearby refugee camp last night, during which one threatened to kill the other.
Officers who arrived at the building arrested the man and four fellow asylum seekers, according to reports.
The German newspaper Express, citing a police spokesman, said the drama broke out after staff felt threatened by “foreign” jobseekers from the district of Muelheim in the city and called in officers. The paper said five people had been arrested, of which four were subsequently released.
It was whilst police were arresting the men that a workers raised the fears of a knife woman on the loose.
Employees were ordered to barricade themselves in their offices and the building was placed on lockdown whilst armed officers searched it, but they discovered nothing.
Cologne Police said in a tweet: “Police operation at job centre in Luxemburger Street due to threatening behaviour. Information over bomb threat is false.”