I regularly hire cars at Nice Airport through hire agents Auto Europe. This company seeks out the best deal and then books a car through one of the mainstream car-hire companies.

In October 2011 I booked a car in the usual way and received a booking confirmation from Auto Europe. This stated that I would be provided with a vehicle through Europcar with a full fuel tank and that I would be required to return it in the same state – which I did.

I was surprised to find I'd been charged an additional £66 for a tank of fuel. Auto Europe replied to my queries but advised me that I signed a docket when I picked up the car, which stated that the hire terms had changed to a "full-to-empty arrangement" and the charge was legitimate. This method of charging doesn't appear to me to be reasonable. I'd warn others to check the fuel option they have selected at the point of pickup as this cost me an extra £66 on top of the original £174 hire, and at no benefit to me. AY, Birmingham

Full-to-empty has become the latest and sneakiest device used by hire-car firms to boost revenues. Several firms now do it, knowing it is impossible to return a car with no fuel. It particularly hits those who don't use the car much during the week, and have to return it half full. Although it was not Auto Europe that set this policy, it has a duty to state the terms of car hire at the time of booking.

Initially, it had told you it was in the rental agreement you signed when you picked up the car – and therefore tough. We asked it for a response, and a change of heart has since occurred. "We did go back to Europcar and requested, as a special exception to their policy and as AY returned with a full tank, which they were able to verify with their location at Nice Airport, to waive this charge. Europcar France has agreed to refund the €73.15 to the credit card which was presented locally," it says.

In the meantime, other travellers booking car hires should look out for this. Check what the fuel policy will be, and if the agent won't tell you, find one that will. Also look out for extra airport charges, especially when booking car hire in Ireland.

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