MEA 7-layer assemblies with gasket, comprising: a film of ionomeric membrane (3), containing functional acid groups —SO3H and/or —COOH, having in at least one direction, called direction x, a size variation lower than 0.08%; two GDL sheets (1) and (2) in porous material having on one surface an electrocatalytic layer, not shown in the Figures, of which: the first sheet DGL (1) is coextensive with the membrane (3) surface, positioned so as to overlap thereto; the second sheet GDL (2), having a lower width but the same length of the film of membrane (3), measured in the x direction; the two sheets (1) and (2) placed so that the electrocatalytic layer comes into contact, respectively, with each of the two membrane faces; a gasket positioned according to a frame shape along the assembly perimeter.