An electrically actuatable parking brake system for a pneumatic braking system includes a control valve device that has a control piston. The parking brake system can assume at least two operating states, namely a parked state or a driving state. The operating states can be assumed in a selective manner dependent on a position of the control piston, and the parked state is provided when the control piston is forced into an end position by the force of a spring that lies in a spring chamber. Leaked air that exits a ventilating connection of the control valve device can be returned into the spring chamber.