According to an aspect, there is provided a method for controlling an elevator system. The method comprises causing transmission of radio frequency signals with at least one radio frequency sensor attached to at least one element movable in an elevator shaft of an elevator system, receiving, from the at least one radio frequency sensor measurement data representing radio frequency signals reflected from at least one object and captured with the at least one radio frequency sensor, causing identification, based on the measurement data, of at least one object; and controlling operation of the elevator system in response to identifying the at least one object based on the measurement data.