A method for the connection of an upper sheet metal part and a lower sheet metal part of which at least one is executed as an organic sheet metal part consisting of a non metallic composite material, with the aid of an auxiliary joining part and at least one metal washer (41, 43) having an aperture, wherein the auxiliary joining part has first and second ends, there being a functional section with an undercut at one of said ends and a piercing section with a lateral shaft surface and a shaft recess formed therein at the other of said ends, the auxiliary joining part being formed as a cylindrical part having a cross-sectional shape and size which, apart from the undercut and the shaft recess, is at least substantially constant over its entire length, the method comprising the following steps: i) the upper sheet metal part, the lower sheet metal part and the metal washer (41, 43) are brought into a stacked arrangement in such a way that the metal washer (41, 43) contacts the organic sheet metal part, ii) the piercing section of the auxiliary joining part is used in order to pierce a slug from the stacked sheet metal part (17, 19), wherein the sheet metal parts (17, 19) are pressed against one another in this step, iii) either the functional section or the piercing section is passed through an aperture of the metal washer (41, 43) until the undercut or the at least one shaft recess is at least partly surrounded by washer material, iv) an adequate pressure is exerted on the metal washer (41, 43) in order to drive washer material into the at least one shaft recess or into the undercut and thereby to join the auxiliary joining part to the metal washer (41, 43), and v) the other respective one of the undercut or of the shaft recess is brought into a holding engagement with a sheet metal part not formed as an organic sheet metal part or with a further metal washer (41, 43), with the sheet metal part not formed as an organic sheet metal part or with the further metal washer being located at the side of the stacked arrangement remote from the first metal washer. i) the upper sheet metal part, the lower sheet metal part and the metal washer (41, 43) are brought into a stacked arrangement in such a way that the metal washer (41, 43) contacts the organic sheet metal part, ii) the piercing section of the auxiliary joining part is used in order to pierce a slug from the stacked sheet metal part (17, 19), wherein the sheet metal parts (17, 19) are pressed against one another in this step, iii) either the functional section or the piercing section is passed through an aperture of the metal washer (41, 43) until the undercut or the at least one shaft recess is at least partly surrounded by washer material, iv) an adequate pressure is exerted on the metal washer (41, 43) in order to drive washer material into the at least one shaft recess or into the undercut and thereby to join the auxiliary joining part to the metal washer (41, 43), and v) the other respective one of the undercut or of the shaft recess is brought into a holding engagement with a sheet metal part not formed as an organic sheet metal part or with a further metal washer (41, 43), with the sheet metal part not formed as an organic sheet metal part or with the further metal washer being located at the side of the stacked arrangement remote from the first metal washer.