When picking up the car at Hertz, they said only an automatic Ford Fiesta 1.0 was available. It didn't seem like the car I reserved, so I paid an extra 140 euros to upgrade to a Volvo V60 Diesel D4 and accepted it. This was because the three major German brands don't allow their cars to leave Germany. At the Vienna airport return counter, a female clerk took the car back without giving any receipt and had a very poor attitude. To avoid complications, I called the Berlin airport rental counter right away. A man named Daniel answered and said he would handle it the next day and send me an email (which I never received). I even had him confirm with the Vienna counter. In the end, the bill showed the return time three days later than the actual return, and I was charged significantly more. Additionally, they charged me in dollars instead of euros using an unfair exchange rate (the receipt showed euros, but they charged 1.14 when the actual rate was 1.10). Always insist on being billed in euros.