The invention relates to a multilayer structure in which the inner layer is in contact with petrol or diesel fuel and comprising, in succession from the outside inwards: an outer layer made of, 50 to 100% of at least one polyamide A1 of formula X.Y/Z or 6.Y2/Z in which: “6” represents the residues of hexamethylene diamine, X denotes the residues of a C6-10 aliphatic, Y denotes the residues of an aliphatic C10-14 dicarboxylic acid, Y2 denotes the residues of an aliphatic C15-20 dicarboxylic acid, and Z denotes at least one unit chosen from the residues of a lactam, the residues of an α,ω-aminocarboxylic acid, the unit X1,Y1 in which X1 denotes the residues of an aliphatic diamine and Y1 denotes the residues of an aliphatic dicarboxylic acid, the weight ratios Z/(X+Y+Z) and Z/(6+Y2+Z) being between 0 and 15%, an inner PA-6 layer or a layer of a PA-6/polyolefin blend having a PA-6 matrix and optionally containing a conductor.