I've lived in Reims for 1.5 years and have rented from at least 4 different agencies here during that time; my 2 rentals from Sixt have been by far the easiest and best customer service experiences. They are very friendly, straightforward and do not try the annoying stuff that other companies try (upselling, saying they don't have the vehicle type you rented, etc). I fully recommend Sixt in Reims.