I feel good about Hertz USA and have always been treated well, but Hertz in Frankfurt Airport, Germany left me with a bad feeling.
Upon return of the car (that had 35,000 KM on it) a tiny dent in the bumper was pointed out as "damage." Even if I had seen this upon car-pickup I would not have had it recorded because of its tiny size.

A week later I received a bill for 1,447 Euros, along with a detailed list of items to be repaired.
Not only did the costs seem excessive, they even charged me for new emblems which seems rather dubious.
I can't help but wonder if any other unnecessary parts were listed.
Have a look at the pictures and you be the judge.
(the damage is directly below the 91 in the license plate)

Hertz is supposed to have a program where a "damage matrix" can be referenced at the rental location to quickly settle minor damage.
The rental agreement specifies this. However, my email request for this was ignored.

My lessons: 1. don't assume Hertz International locations operate the same way as in the USA, 2. have the rental agent mark every blemish on the form before leaving with the car and don't be shy to be a very picky person and point out everything, no matter how tiny because they surely will be picky at return-time, and 3. if you do get accused of minor damage upon return, insist that they show you the "damage matrix" and damage criteria form and try to settle it on the spot rather than wait to receive a bill. If they won't do this, be sure to write on the damage report that they refused.