Mr. Clean, a Proctor and Gamble cleaning product, is known as Mr. Proper in Germany. “Clean” in German is “sauber”, and the “proper” isn’t a German word at all, I think. I don’t quite know what else to say, except what’s the story with Mister Proper?
I’ve never been really comfortable with that Mr Clean fellow. Maybe it’s the eyebrows. 
/bump
Just guessing here, but…maybe the word “proper” filled the Marketing Division’s need for an easily pronounceable English word that connoted “clean, nice, good, desirable”? If you’re a German speaker, it’s probably not easy to pronounce the English word “clean” upon first glance, if you’re not familiar with it. “Cleh-ahn”? And then you’d have to learn "no, it’s pronounced ‘kleen’, and then you’d feel stoopid. P & G wants to avoid making customers feel stoopid.
Just a guess.
Herr Sauber sounds like antabuse.
Herr Korrekt is schoolteacherish.
Proper, in German, means:
1a) Smart (like smartly dressed, not intelligent)
b) Neat and Tidy
c) Meticulous
So it makes sense. My guess is that the brand folks thought Mr. Proper sounded better than Herr Proper.
And it’s Procter, not Proctor. C’mon, Elmwood, you’re in Ohio, you should know that.
That’s northern Ohio, the blue part of the state. At least I didn’t belt out one of my usual typos and call it “Procto and Gamble.” 
Seems like a good answer, though. I tried Babelfish, and couldn’t find a match for “proper” as a German word. Thanks!
Tee-shirts and earrings are back in style!