This is a classic German children's song and a great way to teach colors to anyone.
I've been teaching my (half German/half Norwegian) boyfriend some German vocabulary, and when it came to colors this song immediately came to mind. He wasn't into the idea of singing, but even just hearing it helped him to remember the colors. It's fun too because it teaches some professions - and gives some cultural connections with professions and the colors they wear:
Hunters () wear green (grün).
Sailors (Seemann) wear blue (blau).
Painters (Maler) wear multicolors (bunt)...though maybe not intentionally.
There are a few versions of this song/video online. The above were 2 I liked most because of the way the videos showed the lyrics and how they show how much of a classic song this is for kids.
One thing I can guarantee is that this song will get stuck in your head!