A resin film configured to hold a conductive metallic track against a panel. The resin film partially covers the conductive metallic track, such that the conductive metallic track has at least one region which does not have the resin film, so as to allow an electrical connection by contact. Thus, in the context of assembly on a panel, the metallic track incorporated between the panel and the resin film is protected, thus rendering this technical solution particularly robust. Furthermore, the resin film electrically insulates the metallic track from surrounding elements, and the regions which do not have resin film allow an electrical connection by contact.