Two people were injured by fireworks thrown from the Bayer Leverkusen stands ahead of the 3-2 defeat to Borussia Monchengladbach on Saturday.
Leverkusen are set to be punished by the German Football Association (DFB) following incidents prior to kick-off at the BayArena.
Fans lit fireworks in the home end before throwing them on the pitch, injuring a cameraman and steward in the process, with the former sustaining a foot injury and the latter a blast injury.
"This has no place in the stadium," Leverkusen coach Roger Schmidt told reporters after the match. "It was just like fireworks, a great risk for all. It's a shame. We hope that no lasting harm was done."
In a statement on the club's official website on Sunday, Leverkusen said they do not tolerate "any form of pyrotechnics, violence and discrimination," and that "a group of fans appear to believe a stadium was a legal vacuum."
Leverkusen added that they "will do everything to identify those responsible and make them accountable for it."
Media reports and the club's statement suggest that the supporters used the fireworks to protest the ban of a planned "choreo" (fan display) by Leverkusen's fire brigade and the city of Leverkusen.
The DFB has yet to react, but is likely to open proceedings against Leverkusen, who were fined €14,000 in December for the use of fireworks on two separate occasions during the first half of the season.
Elsewhere, a group of Borussia Dortmund supporters lit fireworks ahead of their club's second half at Mainz on Sunday.
Dortmund are currently playing under a suspended sentence for the use of fireworks on several occasions, and could now face a partial stadium closure for their next home game against RB Leipzig.
However, reports in Germany on Monday said that Dortmund will instead be fined a high five-digit sum, but the Westfalenstadion's Sudtribune will remain open for the Leipzig clash.
The DFB has yet to comment.