Blumenkorso_05 really sets off a bad case of cognitive dissonance. A flower-covered tank (apparently a tank-like replica) with much humor and laughter in the crowd.
Btw, in the US (just in case you didn't know) "flower cars" are those vehicles used to transport floral sprays and wreaths from a funeral "home" (or "parlor") to a cemetery, usually in the funeral cortege behind the hearse and the limousines in which the deceased's family rides...more or less.
Those vehicles that are covered in flowers for parades are usually called "floats." Not to be confused with British "milk floats."
Since I've known parade cars, "floats" have lacked the car shape and are generally built on a bare chassis (last photo.)
I don't know what parade cars/floats are called in other parts of the world...or even different parts of the US. I'd be interested in finding out more, although I've learned a bit about German terminology.
RtR