In a road finishing machine comprising at least one screed, a machine control, and a ventilation system including a fan, the fan can be switched on or off via the machine control automatically independent of the operator and exclusively depending on demand. According to the invention, before or during the laying operation, a defined demand for the operation of the ventilation system is determined, and during or for the laying operation, the ventilation system is operated independent of the operator and automatically, and optionally power-controlled, upon determination of the defined demand.