A number of touts caused trouble at ticketing booths around the city as supporters camped outside for two nights to give themselves a chance of attending the semi-finalBorussia Dortmund's Champions League semi-final against Real Madrid went on sale.
It is believed a number of ticket touts were involved in trying to make their way to the front of queues as supporters waited to get their hands on one of the 66,000 tickets, and violence soon broke out, leading to the police being called.
Fans had camped out for two nights in the hope of seeing their side take on the Spanish champions in the last four of Europe's premier club competition, and were understandably angry at others trying to push in front and obtain tickets to sell on.
Dortmund CEO Hans-Joachim Watzke revealed the club had made a mistake in offering the tickets to the general public and admitted lessons would be learned from this incident.
"We underestimated the run on the tickets. We will draw our lessons and will not have a free sale like this again," he said in a statement.
Due to Uefa restrictions, the club's 80,000 capacity stadium, the Signal Iduna Park, cannot be fully used due to areas being standing only, meaning a number of regular supporters have been left empty-handed in their quest to watch their team on April 24.
One person was taken into police custody following the incidents while a further two were reported for aggravated battery and assault.