Is it illegal to call your son "Judas" in Germany?

I am preparing for a class tomorrow, as part of my course on Non-canonical Gospels, on the Gospel of Judas. While reviewing some video material for possible use in class, I came across this piece from the National Geographic documentary of a few years ago:



At 1:22, William Klassen says, "In Germany, of course, it is illegal to name your child Judas". This sounds like nonsense to me. I found the same claim made by William Klassen, presumably quoting from the same interview, in Herbert Krosney, The Lost Gospel: The Quest for the Gospel of Judas Iscariot (Washington, DC: National Geographic, 2006): 3.   A little googling appears to confirm that there is indeed no law in Germany that prevents parents naming their sons "Judas".  Whether parents are inclined to call their sons Judas, and whether officials might have objected to such naming, are, of course, different questions.