A 17-year-old and 22-year-old were at Wesel train station late on Friday night when they spotted the masked man, who was holding a gun and a knife.
As the two young men approached the clown, he verbally threatened them in both German and English before absconding in an unknown direction.
Police described the man as about 180-185cm tall and wearing a dark, hooded top as well as dark trousers. He was wearing a white clown mask with red lips and a red nose.
The recent so-called “killer clown” craze started in the United States, where dozens of reports and YouTube videos have been made about people in clown costumes, chasing passersby or scaring young children.
The phenomenon has now spread to Europe, with sightings reported in the UK and Sweden.
But what some police departments view as a large-scale prank took a more dangerous turn in a town in Sweden at the weekend when a man was assaulted by three people dressed as clowns, with one using a broken bottle.
Another teen in Sweden was injured by a clown, who cut the young man's shoulder with a knife last week before running away.
Some have even formed clown-hunting groups in the Scandinavian country to track sightings and inform people of what to do should they encounter a clown.