A process for the formation of an assembly comprising a structured or compacted porous film comprising a) application of a porous film (2b) onto an elastic substrate (1b) in a stretched state such that a reversible adhesion of the film on the stretched substrate occurs, and b) relaxing the substrate (1b) with the applied film thereon to obtain a structured or compacted porous film (2a), c) applying a support material to a part of the structured or compacted film so that the structured or compacted film to which no support material is attached is releasable.