Abstract: The invention relates to a method for the manufacture of a pack, particularly intended for undergoing preservation treatment, from at least one film (10) comprising two plastic layers, an upper (11) and a lower (12), which form the outer and inner faces of said pack, and a light-metal central layer (13) sandwiched between said upper and lower layers. According to the invention, prior to the operations to make said pack, a laser beam is applied solely to the lower layer of said film, said lower layer forming the inner face of said pack, in order to produce, virtually in the entire thickness of said lower layer, at least one perforation (14) forming at least one precut line.