Abstract: A propulsion assembly for an aircraft, the assembly including a turbojet having at least one unducted propulsive propeller, and an attachment pylon for attaching the turbojet to a structural element of the aircraft, the pylon being positioned on the turbojet upstream from the propeller and having a streamlined profile defined by two opposite side faces extending transversely between a leading edge and a trailing edge. The pylon includes a plurality of blow nozzles situated in the vicinity of its trailing edge and configured to blow air taken from a pressurized portion of the turbojet, the blow nozzles being positioned over at least a fraction of the trailing edge of the pylon that extends longitudinally facing at least a portion of the propeller. A method of reducing the noise generated by a pylon attaching a turbojet to an aircraft is presented.