Picking up and dropping off the car at Frankfurt Airport is very convenient. There's a counter in the arrival hall where you can complete payment and then go to the underground parking level 1 to get the car. Returning the car was a bit tricky, however. The navigation led us to the lower levels (B2 and B3) of the parking lot. After driving around and exiting, we asked the security at the exit and found out that the entrance to the rental car parking area on B1 is near the parking exit via a small ramp. It would be great if the navigation could direct us to that ramp directly. When returning the car, three people inspected it thoroughly, showcasing German meticulousness. In contrast, in France, a single person glanced at it and said it was okay.