The sealing element for integration into a sealing tool for producing smooth stamping fields during the sealing of two plastic sheets has a base body. A first slot extends into the base body from a first narrow lateral surface, and a second slot, which is offset vertically from the first slot, extends into the base body from a second narrow lateral surface, in such a way that the two slots define a section of the base body which has substantially the shape of an S or reversed S. The first slot has a U-shape with a first leg of the first slot being longer than a second leg of the first slot, and the second slot has a U-shape with a first leg of the second slot being longer than a second leg of the second slot. Each of the two slots expands at its inner end to form a bore.