MUNICH — For Reinhard Grindel, the leader of Germany’s soccer federation, this has become an awkward moment to promote his country’s campaign to stage European Championship in 2024, or, really, anything having to do with a national team program that only months ago was considered a symbol of unity for the country and one of the most unstoppable forces in sports.

Earlier this month, a mob waving German flags and flashing Nazi salutes rampaged through the streets of Chemnitz, in eastern Germany, chasing dark-skinned bystanders as the police, for a time outnumbered, could only watch.

After the images were broadcast around the world, they became yet another event for Grindel and the German federation to explain away. For weeks, the federation, known as the D.F.B., has attempted to answer accusations of racism and discrimination stemming from the ugly departure this summer of Mesut Özil, a World Cup-winning playmaker, from the national team after a historically awful performance from the defending world champions in the World Cup.

“I’m a German when we win, but I am an immigrant when we lose,” Özil wrote in a lengthy screed a week after the end of the World Cup, in which Germany finished last in its group, its worst showing since 1938.