A policewoman was injured during an inspection before the soccer game between FC Schalke 04 and SG Dynamo Dresden on Saturday evening in Gelsenkirchen.
A police spokesman said an unknown person escaped control by escaping the control and hit the policewoman.
How badly the policewoman was injured was initially unclear.
Gelsenkirchen - She was taken to a hospital for an examination.
The police in Gelsenkirchen could not say whether the stranger was a Dresden fan, as the media had previously reported.
That is the subject of the investigation.
The car had previously left the motorway.
dpa