Which is, in the broad sense, a subcategory of criminal law (as opposed to civil law).

This is at least wrong in Germany, they are handled by different courts, will not show up on criminal record etc., it's more like a civil case, but with the government. Though of course you could park your car so horribly that it might get to be one, there's criminal neglect.

Erm ... in which sense exactly is an Ordnungswidrigkeitenverfahren like a Zivilprozess? How are the courts different?

Also, yes, "but with the government" is exactly what makes it a criminal case!?

See also:

https://de.wikipedia.org/wiki/Ordnungswidrigkeit

https://de.wikipedia.org/wiki/Strafrecht_(Deutschland)

Sorry, I was wrong about the courts, but at first it is not even handled by a court or prosecutor at all, only by the administration. If the potential fine is not accepted it then indeed goes to criminal court.

Well, yes, Ordnungswidrkeiten are "Straftaten light", if you will, so consequences are generally less severe, the process has a shortcut for undisputed cases, ... but the essence is still that the state makes a member of society experience some consequences for not following the law, and thus in particular the same constitutional protections apply.