A system (100) for controlling a rotorcraft (1) including a rotor (10), at least one variable-pitch propulsion propeller (6L, 6R), and a motor (5) for driving the rotor and the propeller(s), the system includes: a member (101, 101A, 102, 103, 104) for generating a propeller pitch setpoint (θp*+θd*, θp*−θd*) as a function at least of a thrust variation command (TCL); a member (105, 105A) for generating a setpoint (RPM*) for the drive speed (RPM) of the rotor and the propeller(s), as a function at least of the travel speed (VTAS) of the rotorcraft; and a member (106) for generating a setpoint (NG*) for the engine speed as a function at least of the thrust command (TCL), of the drive speed setpoint (RTM*), and of a rotor collective pitch command (θ0).