Sixt

SIXT is not at the airport. You have to find a telephone number (no Information at the airport) and call for a shuttle to the Harbour. The shuttle van came quickly and the driver was friendly.
The manager at the desk was a completely different matter. We had pre-​booked and pre-​paid for a 10 day rental, but we were refused a car when the manager did not accept my driver’s license and passport as sufficient ID. Apparently SIXT requires other documentation such as an electric bill. After the fact I’ve read online about other people having the same problem with SIXT. The manager was rude and unhelpful. He told my husband to keep quiet. We were calm and respectful during the interaction and were shocked when he walked out of the office and left us standing at the counter. We took the shuttle back to the airport and got a car from Enterprise in 5 minutes. I’ll never use SIXT again and advise you to avoid them.