Is racism widespread in Germany? No. Is discrimination prevalent in German society? Yes. While both of these phenomena are noticeable in Düsseldorf too, the level of occurrence is minimal? However, each individual incident is a crime and an affront to a human being.
Your publisher is white, male and from England. Being British and carrying a UK passport also defines me. I have never faced personal racism, even when living in areas of the world in a minority, including Düsseldorf and areas of London. Have I felt discrimination? Not consciously? No Exclusion? Yes.