A control system for controlling at least one rotor of a rotorcraft, the control system comprising at least one piloting member suitable for operating at least one control for controlling movements of the at least one rotor. Such a control system comprises: at least one memory enabling information representative of a predetermined control margin threshold to be stored; calculation means for calculating a current control margin, which margin is defined as being the difference between a current position and a limit of the control for controlling movements of the rotor(s); comparator means for comparing the current control margin with the predetermined control margin threshold; and a control unit for modifying an operating relationship of the control for controlling movements of the rotor(s) when the current control margin is less than or equal to the predetermined control margin.