A multi-layer polymer film comprising at least one middle layer A, the polymeric constituents of which are soluble in aqueous solution, and in each case at least one substantially water-impermeable covering layer B, C arranged above and below the at least one middle layer A, wherein the layers A, B and C independently of each other in each case comprise at least one thermoplastic polymer and at least one of the covering layers B and C comprises at least one polyhydroxyalkanoate is presented and described. Processes for the production of the multi-layer polymer film according to the invention and its use for the production of molded parts, films or bags are furthermore presented and described.