Hannover have been fined €20,000 after Mainz players Leon Balogun and Anthony Ujah were racially abused during a Bundesliga match last month.
The German FA (DFB) ruled on Thursday that Hannover would be fined for "unsporting behaviour of their fans" for incidents at the match on Jan. 13.
The DFB said on their website that "a group of seven to 12 persons racially abused, over large parts of the second half, the two Mainz players Leon Balogun and Anthony Ujah, who were warming up near the goalline."
After the incidents were highlighted by Balogun on social media, Hannover immediately apologised, and sporting director Horst Heldt said: "We are dismayed. Such behaviour cannot be tolerated, not in a stadium and not elsewhere."
Hannover have already identified two perpetrators and handed both a stadium ban, the club said in a press release on their official website.
Hans E Lorenz, a judge at the DFB sports court, said Hannover's swift action and their "zero tolerance politic" against racism in recent years were taken into consideration when imposing the fine on the club.