The animal, who is male and thought to be around 70-years-old, had a lucky escape when he walked onto a busy crossroads junction in the North Rhine-Westphalia city, police said.
The incident happened on Monday afternoon in the Rodenkirchen district – and several drivers were forced to emergency brake in order to avoid hitting the tortoise.
Emergency services were called out to the scene and described the tortoise as a "sprightly senior". The tortoise stepped out onto the road around 2.30pm.
The tortoise "ignored other road users, blocked the road and did not let himself be unnecessarily rushed, consistently disregarding all traffic rules," joked the police.
READ ALSO: Man tries to smuggle tortoises disguised as deserts through Berlin airport
Officers "temporarily" took the tortoise into custody due to his behaviour. He was then taken to an animal shelter.
According to the police, the tortoise had either been abandoned or, after waking up from hibernation, had managed to escape from an enclosure.
Animal keepers said the tortoise was in good health apart from a slightly damaged shell and claws which were too long.