LN-DYE was parked on the ramp with remote stairs for boarding. They were ready to go and the cabin crew was about to close the forward entrance door, with one fot in the aircraft and one fot on the stairs. At the same time the stairs were driven away. The person from the cabin crew fell down 2,6 m. The person was injured, including foot fractures, which resulted in a hospital stay. Only coincidence prevented more serious injuries. Both the airline company and the ground handling operator have changed their procedures: The cabin crew must have both feet inside the aircraft when closing the doors. If available ground personell might be asked to assist the cabin crew from outside. The Ground Handling operator must communicate with the cabin crew before ground support equipment can be removed.