A door frame of a shaft door is provided for an elevator system having an elevator shaft accessed through the shaft door. The door frame forms a chamber accommodating a control unit for the elevator system. The door frame has a side surface facing the elevator shaft, a first door frame element delimiting the chamber and a second door frame element delimiting the chamber. The first door frame element can be detached from the second door frame element by a movement of the first door frame element, from its closed position, in parallel with the side surface, to open the chamber. The invention also relates to an elevator system (2) comprising such a door frame (22).