Assembly for an aircraft, said assembly comprising: - a pylon with an upper spar, two lateral panels that extend vertically beneath the upper spar and four lateral scoops (212a-b), each one being fastened on the outside against a lateral panel beneath the upper spar, with two lateral scoops (212a-b) per lateral panel and, per lateral panel, there is one lateral scoop at the rear of the pylon and one lateral scoop generally in the middle of the pylon, - a wing having a skin, longitudinal spars (206a-b) and fittings that are fastened both to the inside of the skin and to the longitudinal spars (206a-b), and - for each lateral scoop (212a-b), two fastening assemblies, wherein, for each fastening assembly, the skin and the fitting each have a first bore, which bores extend one another, and the upper spar and the lateral scoop (212a-b) each have a second bore, which bores extend one another, wherein each fastening assembly has: - a screw passing through the first bores and the second bores, and having a plain zone on the side of its head and a threaded zone opposite its head, - a nut screwed onto the threaded zone of the screw, characterized in that the assembly comprises: - an inner eccentric ring, having a barrel and a shoulder, wherein the inner surface of the barrel and the outer surface of the barrel are cylinders of revolution that are offset with respect to one another, wherein the inner eccentric ring is threaded onto the plain zone of the screw, - an outer eccentric ring, having a barrel and a shoulder, wherein the inner surface of the barrel and the outer surface of the barrel are cylinders of revolution that are offset with respect to one another, wherein the outer eccentric ring is threaded onto the inner eccentric ring, wherein the two eccentric rings (256, 258) are housed and mounted with a close fit in terms of diameter in the second bores, and - a rotation stopping system (260, 460) that prevents the rotation of the eccentric rings (256, 258), wherein, between the head of the screw and the nut, there are successively sandwiched the shoulder of the inner eccentric ring, the shoulder of the outer eccentric ring, the lateral scoop (212a-b), the upper spar, the skin, and the fitting. - a pylon with an upper spar, two lateral panels that extend vertically beneath the upper spar and four lateral scoops (212a-b), each one being fastened on the outside against a lateral panel beneath the upper spar, with two lateral scoops (212a-b) per lateral panel and, per lateral panel, there is one lateral scoop at the rear of the pylon and one lateral scoop generally in the middle of the pylon, - a wing having a skin, longitudinal spars (206a-b) and fittings that are fastened both to the inside of the skin and to the longitudinal spars (206a-b), and - for each lateral scoop (212a-b), two fastening assemblies, wherein, for each fastening assembly, the skin and the fitting each have a first bore, which bores extend one another, and the upper spar and the lateral scoop (212a-b) each have a second bore, which bores extend one another, - a screw passing through the first bores and the second bores, and having a plain zone on the side of its head and a threaded zone opposite its head, - a nut screwed onto the threaded zone of the screw, - an inner eccentric ring, having a barrel and a shoulder, wherein the inner surface of the barrel and the outer surface of the barrel are cylinders of revolution that are offset with respect to one another, wherein the inner eccentric ring is threaded onto the plain zone of the screw, - an outer eccentric ring, having a barrel and a shoulder, wherein the inner surface of the barrel and the outer surface of the barrel are cylinders of revolution that are offset with respect to one another, wherein the outer eccentric ring is threaded onto the inner eccentric ring, wherein the two eccentric rings (256, 258) are housed and mounted with a close fit in terms of diameter in the second bores, and - a rotation stopping system (260, 460) that prevents the rotation of the eccentric rings (256, 258), wherein, between the head of the screw and the nut, there are successively sandwiched the shoulder of the inner eccentric ring, the shoulder of the outer eccentric ring, the lateral scoop (212a-b), the upper spar, the skin, and the fitting.