It’s fictional, of course, just like George Washington and the Cherry Tree. The King of Denmark did not go around on a bicycle wearing a Jewish star badge to protest the Nazis. But Leon Uris created the legend, and when legends become facts, you go with the legend. So a tee-shirt with the yellow star and the word Jude or in France Juif on it would serve as a “King of Denmark” protest against anti-Jewish violence such as was perpetrated in Toulouse.
I prefer him riding a horse. Kings don’t ride bicycles. Can’t do a painting of a King on a bike. I’m not sure that Jews in Denmark wore stars. And the Danes did a better job than most of Europe saving Jews. Gone to Sweden, where they’re less than safe today. I guess times don’t change in many ways.