The subject of the invention is a propulsion assembly comprising at least one jet pipe (62, 76) comprising an air outlet delimited by a trailing edge (78, 82), characterized in that the end portion of the jet pipe (62, 76) has two notches (84) each corresponding to one favoured direction of acoustic radiation, these being separated by protruding portions (86) capable of limiting the acoustic radiation, and the said notches being offset upwards relative to the horizontal midplane.