A rigid packet of smoking articles comprising: a parallelepiped-shaped container having an open top end, a bottom wall, a front wall, a rear wall, and two lateral walls; a parallelepiped-shaped lid hinged to the container and having a top wall, a front wall, a rear wall, and two lateral walls; an inner package which encloses a group of smoking articles, is housed inside the container and is smaller in cross section than the container; and a collar, which surrounds the inner package, is glued to the inside of the container, projects from the open top end of the container and has a front wall which is superimposed on and glued to the front wall of the container, two lateral walls which are superimposed on and glued to corresponding lateral walls of the container; wherein at least one lateral wall of the collar is spaced apart from a corresponding lateral wall of the inner package so as to define, together with the corresponding lateral wall of the inner package, a lateral chamber not occupied by the inner package; wherein the collar comprises at least a box body, which cantilevering projects from a corresponding lateral wall and is arranged inside the lateral chamber; the packet of smoking articles being characterized in that the box body of the collar comprises: a first panel which is arranged perpendicular to the lateral wall and parallel to the bottom wall of the container, is connected to the lateral wall itself, and closes the lateral chamber; a second panel which is arranged parallel to the lateral wall and rests on a corresponding lateral wall of the inner package and is connected to the first panel; a third panel which is arranged perpendicular to the lateral wall and parallel to the first panel and to the bottom wall of the container, is connected to the second panel, and closes the lateral chamber; and a fourth panel which is arranged parallel to the lateral wall, is superimposed on and glued to the lateral wall itself, and is connected to the third panel. a parallelepiped-shaped container having an open top end, a bottom wall, a front wall, a rear wall, and two lateral walls; a parallelepiped-shaped lid hinged to the container and having a top wall, a front wall, a rear wall, and two lateral walls; an inner package which encloses a group of smoking articles, is housed inside the container and is smaller in cross section than the container; and a collar, which surrounds the inner package, is glued to the inside of the container, projects from the open top end of the container and has a front wall which is superimposed on and glued to the front wall of the container, two lateral walls which are superimposed on and glued to corresponding lateral walls of the container; wherein at least one lateral wall of the collar is spaced apart from a corresponding lateral wall of the inner package so as to define, together with the corresponding lateral wall of the inner package, a lateral chamber not occupied by the inner package; wherein the collar comprises at least a box body, which cantilevering projects from a corresponding lateral wall and is arranged inside the lateral chamber; the packet of smoking articles being characterized in that the box body of the collar comprises: a first panel which is arranged perpendicular to the lateral wall and parallel to the bottom wall of the container, is connected to the lateral wall itself, and closes the lateral chamber; a second panel which is arranged parallel to the lateral wall and rests on a corresponding lateral wall of the inner package and is connected to the first panel; a third panel which is arranged perpendicular to the lateral wall and parallel to the first panel and to the bottom wall of the container, is connected to the second panel, and closes the lateral chamber; and a fourth panel which is arranged parallel to the lateral wall, is superimposed on and glued to the lateral wall itself, and is connected to the third panel. a first panel which is arranged perpendicular to the lateral wall and parallel to the bottom wall of the container, is connected to the lateral wall itself, and closes the lateral chamber; a second panel which is arranged parallel to the lateral wall and rests on a corresponding lateral wall of the inner package and is connected to the first panel; a third panel which is arranged perpendicular to the lateral wall and parallel to the first panel and to the bottom wall of the container, is connected to the second panel, and closes the lateral chamber; and a fourth panel which is arranged parallel to the lateral wall, is superimposed on and glued to the lateral wall itself, and is connected to the third panel.