In international soccer, when a national team player retires, it is usually a bittersweet affair. But in the case of German midfielder Mesut Özil, it has set off a firestorm over immigration and racism.

Mr. Özil has been one of Germany’s biggest stars over the past decade. Of Turkish descent, he has been held up as a symbol of German multiculturalism.

But his Turkish heritage has posed challenges, particularly when he appeared in a photo in May with Turkish President Recep Tayyip Erdoğan, who has a famously tense relationship with Germany. Özil said the shot was innocent, but for many, it was politically loaded.

Then came Germany’s crash out of the World Cup last month. Though it was hardly his fault, Özil became a scapegoat, even for football association leadership. He lost sponsorships. He was lambasted in the press.

For Özil, it looked as if the football world that once feted him had turned racist. “I am German when we win, but I am an immigrant when we lose,” he tweeted in his retirement announcement Sunday.

But Özil’s decision has set off a greater discussion. Has Germany done enough to embrace its citizens of multiple national loyalties? What should be done about the xenophobic undertone that has been exposed in German society?

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