A process for producing a metallizable, sealable, biaxially stretch-oriented multi-ply film includes the steps of: providing melts of a predominantly polypropylene base layer, and first and second polyolefinic facing layers; co-extruding the melts through a flat film die, wherein the first and second polyolefinic facing layers are co-extruded on either side of the base layer; solidifying the co-extruded film by cooling; longitudinally stretching the co-extruded film at a temperature from about 120.degree. to 130.degree. C. in a ratio of from about 5 to 7:1; transversely stretching the co-extruded film at a temperature from about 160.degree. to 170.degree. C. in a ratio of from about 8 to 10:1; and corona-treating one facing layer of the co-extruded film which is metallizable. Each of the melts contains a calcium carbonate neutralizing agent having an absolute particle size of less than about 10 .mu.m, a mean particle size of less than about 0.1 .mu.m, a specific surface area of more than about 40 m.sup.2 /g and a whiteness of more than about 90%, and also a phenolic stabilizer against thermal degradation which has a molecular weight of more than about 1,000 g/mol, and wherein one polyolefinic facing layer contains an anti-blocking agent.