An assembly having a pylon with an upper spar and four lateral scoops, a wing with a skin, longitudinal spars and fittings, and, for each lateral scoop, two fastening assemblies, wherein the skin and the fitting each have a first bore and wherein the upper spar and the lateral scoop each have a second bore, wherein each fastening assembly has a screw passing through the first and the second bores, a nut, two eccentric rings, threaded onto one another and onto the screw, and a system for stopping the eccentric rings rotating. The assembly makes it possible to dispense with the use of the spigots while also ensuring the reaction of the shear forces contained in the XY plane by the bolts on account of the reduced tolerances between the various bores, the external and internal surfaces of the eccentric rings and the plain zones of the screws.