A packing method for producing a rigid, swing-open packet of cigarettes comprising: two inner packages each containing a wrapped group of cigarettes; two inner containers each housing a respective inner package and formed by folding an inner blank; an outer container, which houses the inner containers, has two open lateral ends, and is formed by folding an outer blank having a first panel forming a bottom wall; a second panel forming one lateral wall; a third panel forming a top wall; and a fourth panel (12") forming another lateral wall; the first panel having two connecting tabs separated from the first panel by respective longitudinal fold lines; the second panel having two first retaining tabs separated from the second panel by respective longitudinal fold lines, and the fourth panel (12") having two second retaining tabs separated from the fourth panel (12") by respective longitudinal fold lines; and the third panel having two inner flaps separated from the third panel by respective longitudinal fold lines; and two connecting hinges each connecting a respective inner container to the outer container and formed in the first panel to allow the inner container to rotate between a closed position, in which the inner container is inserted inside the outer container, and an open position, in which the inner container is at least partly extracted from the outer container; the packing method comprising the steps of: forming the inner packages on a first packing unit; depositing each inner package on a respective inner blank; folding each inner blank about a respective inner package to form the inner container on a second packing unit; depositing the two side by side inner containers on the outer blank; and folding the outer blank about the inner containers to form the outer container on a third packing unit; the packing method being characterized by comprising the further step of inserting a spacer between the rear walls of the inner containers, as the first panel is folded 90° with respect to the second panel onto the bottom walls of the inner containers. two inner packages each containing a wrapped group of cigarettes; two inner containers each housing a respective inner package and formed by folding an inner blank; an outer container, which houses the inner containers, has two open lateral ends, and is formed by folding an outer blank having a first panel forming a bottom wall; a second panel forming one lateral wall; a third panel forming a top wall; and a fourth panel (12") forming another lateral wall; the first panel having two connecting tabs separated from the first panel by respective longitudinal fold lines; the second panel having two first retaining tabs separated from the second panel by respective longitudinal fold lines, and the fourth panel (12") having two second retaining tabs separated from the fourth panel (12") by respective longitudinal fold lines; and the third panel having two inner flaps separated from the third panel by respective longitudinal fold lines; and two connecting hinges each connecting a respective inner container to the outer container and formed in the first panel to allow the inner container to rotate between a closed position, in which the inner container is inserted inside the outer container, and an open position, in which the inner container is at least partly extracted from the outer container; forming the inner packages on a first packing unit; depositing each inner package on a respective inner blank; folding each inner blank about a respective inner package to form the inner container on a second packing unit; depositing the two side by side inner containers on the outer blank; and folding the outer blank about the inner containers to form the outer container on a third packing unit; the packing method being characterized by comprising the further step of inserting a spacer between the rear walls of the inner containers, as the first panel is folded 90° with respect to the second panel onto the bottom walls of the inner containers.