Isaiah Lopaz is a black American living in Berlin. On a regular basis Germans ask him where he comes from. No, no, where he really comes from. He’s a college-educated artist and writer — who is frequently mistaken for a drug dealer.

The influx of more than a million migrants into Germany the past two years has forced the country to wrestle with issues of race, ethnicity and identity. Mr. Lopaz says that he feels that Berlin is home, but also that the issues the migrants face have been a part of his world since he moved to Germany nearly a decade ago.

Mr. Lopaz, 36, found a creative way to address instances of racism: He took the offending comments and put them on T-shirts. He then directed a series of portraits taken by his best friend, Richard Hancock, around Berlin. I talked to Mr. Lopaz multiple times about the stories behind some of his T-shirts. His comments have been edited.