A folding box for packing food products such as cakes, comprising a container portion and a lid portion, the container portion comprising a base panel and four sidewalls, namely a rear wall, a front wall and two sidewalls, the lid portion comprising a top panel and three sidewalls, namely a front wall and two sidewalls, the top panel being pivotably attached to an upper edge of the rear wall of the container portion, so that the lid portion can be closed by pivoting said lid portion forward until the top panel is essentially parallel to the base panel, and wherein: - the front wall of the container portion is pivotably attached to the base panel and not to the sidewalls of the container portion, - the front walls (7,16) of the container portion and the lid portion are respectively provided with a lip and an opening, the lip being configured to be inserted in said opening for securing the box after closing the lid portion and folding up the front wall of the container portion, characterized in that: - the lip is a foldable cut-out of the container portion's front wall comprising a rear edge formed by a fold line connected to said container portion's front wall, two side edges and a front edge, - the front edge comprises a centrally placed protrusion, - the side edges are inclined towards each other and provided with symmetrically placed tooth sections, - the opening in the front wall of the lid is a slit comprising a flat portion and two upwardly inclined side portions, the flat portion being configured to first receive therein the protrusion of the lip when the lip is inserted in the slit, - the distance (a) between the tips of the tooth sections is slightly higher than the length (w) of the flat portion of the slit, so that the continued insertion of the lip into the slit requires overcoming a resistance by snapping the tips of the tooth sections past the ends of the flat portion of the slit. - the front wall of the container portion is pivotably attached to the base panel and not to the sidewalls of the container portion, - the front walls (7,16) of the container portion and the lid portion are respectively provided with a lip and an opening, the lip being configured to be inserted in said opening for securing the box after closing the lid portion and folding up the front wall of the container portion, - the lip is a foldable cut-out of the container portion's front wall comprising a rear edge formed by a fold line connected to said container portion's front wall, two side edges and a front edge, - the front edge comprises a centrally placed protrusion, - the side edges are inclined towards each other and provided with symmetrically placed tooth sections, - the opening in the front wall of the lid is a slit comprising a flat portion and two upwardly inclined side portions, the flat portion being configured to first receive therein the protrusion of the lip when the lip is inserted in the slit, - the distance (a) between the tips of the tooth sections is slightly higher than the length (w) of the flat portion of the slit, so that the continued insertion of the lip into the slit requires overcoming a resistance by snapping the tips of the tooth sections past the ends of the flat portion of the slit.