Do I need to return the car with a full tank of fuel? 

If the renter does not choose to purchase an optional fuel product at the start of the rental period and does not return the vehicle with the same level of fuel as at the start of the rental period (as indicated on the Rental Agreement) the renter will be required to pay a re-fuelling service fee calculated as the difference between the fuel level recorded on your Rental Agreement and that recorded upon the return of the Vehicle  multiplied by the fuel price displayed at the branch, plus a refuelling charge of 10 EUR. Unused or excess fuel will not be refunded.