The offices of Borussia Dortmund and the office of Dortmund president Reinhard Rauball were vandalised late on Wednesday night, local radio 91.2 reports.
According to the radio station five to six masked men threw paint bombs against the storefront. Local papers left it open as to whether the paint bombs were connected with Wednesday's vote on the Safe Stadium Experience paper, but there is certainly a connection to be drawn as Rauball is also the German Football League president.
"Obviously, BVB fans wanted to show their resistance against the DFL paper," Dortmund CEO Aki Watzke told the official club website. "The resulting damage goes way into four digits. I must say, personally I am utterly disappointed over such a behaviour. We will not be pressured by criminal behaviour."
Borussia Dortmund fans had previously voiced their disappointment on the club's decision to vote in favour of the controversial paper, though Watzke believed not all of it was justified.
"We received criticism. But some of it was based on a lack of knowledge of what was decided in Frankfurt," he said. Despite the vote going ahead on Wednesday afternoon, the paper was not made public until late on Thursday afternoon. "I was surprised by the late release," Watzke added.
He also revealed that Dortmund voted against the clause that enables home clubs to reduce capacity for away fans by notifying the German FA.
He said: "We could not be in favour of that clause and voted against it. I am however a democrat and have to accept a majority."