The invention relates to a method, a device and packaging obtained by way of the method, for fitting at least one reinforcement at a given location on a cutout of cardboard sheet or corrugated cardboard suitable for forming the packaging. The blank is removed from a store with the aid of unstacking means comprising a longitudinal structure with a given shape, the blank is transferred horizontally above a template for forming said blank, the blank is compressed between the template and said longitudinal structure, the blank thus configured is transferred with glue being applied to the side edges and the blank thus glued is applied to the cutout at the given location so as to form the reinforcement of said packaging.