A planar flexible electrode arrangement for a dielectric barrier plasma discharge has a central region (107) and an edge region (108) and at least one planar electrode (102) to which a high-voltage potential can be applied and which is embedded in a planar dielectric (101) that forms an upper face (103) and a contact face (104), wherein the planar dielectric (101), at least in the edge region (108), has the shape of a spiral-shaped wound-up strip (109) and the at least one electrode (102) is formed by at least one electrical conductor (114) that extends in the longitudinal direction of the wound-up strip (109) and that opens into an end face of the strip (109), which conductor (114) is surrounded, with the sole exception of the end face of the strip (109), by the dielectric of the strip (109) and, in the region of the end face of the strip (109), is electrically insulated from the surroundings by a cover element (116). The electrode arrangement can be adapted easily, and without tools, in its bearing surface to the size of the area of a surface that is to be treated, by virtue of the fact that material recesses (111) are present across the width of the strip (109), and that the material of the dielectric (101) and of the at least one conductor (114) is chosen such that the strip (109), together with the at least one conductor (114), can be torn off across its width along the material recesses (111).