Abstract: The invention relates to a strip having a longitudinal reinforcement; a packaging method comprising such a strip; an installation and a machine for implementing the packaging method and a device for the production of such a strip. This flexible strip (1), which is more specifically applicable to the construction of packaging, constituted more specifically by a plastic film, of the integrally produced type, wherein it possesses at least one longitudinal zone of reinforcement (2) constituted, at least in part, by N longitudinal zones of folding (3a, 3b, 3N) of the strip (1), adjacent to one another, overlapping one another at least substantially flatly, at least in part, in a single longitudinal region of the strip (1), N being a positive integer at least equal to two.