There used to be a website called You Park Like An Asshole that had pre-designed flyers you could attach to cars like this and other such infractions of, uh, good parking etiquette, if not also laws.

Looks like the site is dead, and either way, the other comments suggest this is in a country where the primary language isn't English so their flyers wouldn't be as useful.

... but it doesn't mean that you can't design your own in the local language and shove it under their windscreen wiper. Bonus points for putting it in a sticky-backed plastic envelope. You know. The things that parking tickets usually get put in.