The spokesman for the northern town, known as Hameln in German, said the sharp rise in the furry pests at an abandoned garden allotment site on the edge of the town was because the rats had a plentiful supply of food from a makeshift rubbish dump.
"There's a specific problem" that has led to an "explosion" in the number of rats, spokesman Thomas Wahmes told daily paper Die Welt.
He admitted the plot had become a "real refuge" for the unwanted rodents, but cautioned there wasn't a plague of rats like the during the times of the Pied Piper.
According to the famous legend, a colourful or "pied" rat catcher lured all the rats out of town in 1284 by playing his pipe. When the townspeople refused to pay him, he did the same with Hamelin's children and they were never seen again.