Uefa have started disciplinary proceedings against the German Football Association over the "improper conduct" of fans in the 2-1 win over Denmark.
Germany have been charged over fans letting off fireworks and "the displaying of inappropriate banners and symbols, and inappropriate chanting".
Observers from anti-discrimination group FARE have reported seeing a neo-Nazi banner in the Germany section.
Uefa are set to deal with the case on Saturday.
The German Football Association (DFB) has already been fined %uFFFD10,000 over supporter behaviour following the 1-0 win over Portugal.
Fans pelted Portugal players with rolled up pieces of paper in the opening game in Lviv on 9 June.