At least 10 individuals are considered to have been hurt, local press report. A police spokesman said the driver was arrested.
Nature and the rationale of this episode are yet unclear.
Quantities of emergency employees are in the scene in the city, which is located in Germany that is western.
The episode happened during parties for Rosenmontag, or Rose Monday – a carnival day around the nation.
Local reports say a silver Mercedes drove to a group of individuals at around 14:30 local time (13:30 GMT).
Pictures on social websites reveal a vehicle matching that description.
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