A system includes a linear-displacement fluidic actuator coaxial with the propeller, and a transmission device connecting the actuator to the blades that are to be controlled. The transmission device includes at least two radial arms arranged symmetrically with respect to the actuator and connected, on the inside, to a translationally mobile part of the actuator and, on the outside, to a translationally movable rotary transmission ring which is connected to the pivot pins of the blades by intermediate connecting mechanisms that convert the translational movement of the rotary ring brought about by the actuator into a rotation of the blades of the propeller.