Hopefully my educated guess is correct in attributing this to Tropen, and thus I'm posting in the correct place!
Got this given to me at Christmas, and finally got around to posting some pics in the hopes that someone can tell me something about it. The cap, I suspect is from a Waterman (and pretty beaten up at that), but the rest of the pen appears to be in mint condition. Feels surprisingly well-built, the nib being the only thing that lets it down a little; it's one of those pinched together tips. Only markings are the "Cadillac" on the barrel, and "Dauer Feder 1" on the nib (which is what lead me here to Other European brands). Syringe filler (is that the correct term in this instance?), and funky inlaid metal design on the hood. I know its value is likely the square root of zero, but I haven't quite been able to bring myself to ink it up yet; it's so clean and shiny!
If anyone can tell me anything at all, I'd be fascinated to know. Thank you muchly.