The car provided by Caro exceeded expectations with no additional fees. The staff was excellent, answering every question we had with detailed and serious attitudes. However, one car in our group mistakenly used gasoline instead of diesel due to a lack of knowledge, disrupting our trip and incurring high repair costs, which became a major issue for our travel. Upon returning, I carefully read the rental order email and noticed a mention of this issue in the pickup instructions. Honestly, we never expected a small car to use diesel before going to Germany. Years of driving in our home country made us think all small cars use gasoline. If our friends hadn't made this mistake, I wouldn't have known whether we would have made the same error on our first refuel. The thought still worries me! It would be great if the rental staff could spend a minute to show us the fuel type by opening the fuel cap, preventing such mistakes. Therefore, I strongly suggest including a note about fuel type during car handovers, especially in international rentals!