A packaging comprising, on the one hand, a container, of plastic, comprising lateral walls (20, 21, 22, 23) meeting at corners, an upper opening and a bottom, and on the other hand, a detachable lid of plastic configured to cover the upper opening of the container, and wherein the container is provided at the upper opening thereof with a first engagement portion bearing an outwardly directed ridge, and extending over the periphery, said lid being provided over the peripheral part thereof with a second engagement portion extending folded downward provided with an inwardly directed ridge which is able to latch below the outwardly directed ridge of the container, and wherein the second engagement portion of the lid has a skirt extending over the lower part of the second engagement portion, and wherein the outwardly directed ridge of the container, on the one hand, and the inwardly directed ridge of the lid, on the other hand, have curved corner sections (29, 43) in the corners where said lateral walls meet, said curved corner sections connecting the lateral sections of the respective ridges, where at least one of the curved corner sections of the inwardly directed ridge is provided with a foldable skirt section, articulated in a folding area at the upper part of the second engagement portion which is able to be folded from an engagement position to an outwardly directed position in such a way that a central part of said at least one corner section of the inwardly directed ridge is separated by a levering effect of the outwardly directed ridge of the upper opening, and that the engagement between the ridges (28, 41) is thus weakened over the central part, and wherein said foldable skirt section is separated from the remaining section of the skirt by means of two grooves formed in the outer surface of the skirt and extending downward from a folding area to a lower edge of the skirt, said grooves reducing the thickness of the wall of the skirt in such a way that the skirt can be broken along the grooves in order to fold the foldable skirt section from the engagement position thereof toward the outwardly directed position thereof characterized in that the first engagement portion of the container bearing the outwardly directed ridge extends and is elongated below the ridge, referred to as first ridge, and ends below the first ridge by a second ridge, also outwardly directed having a curved corner section, and wherein the foldable skirt section bears at least one lug, inwardly directed, which in the position of engagement of the foldable skirt section is able to latch below the second outwardly directed ridge of the first engagement portion, at least when a force is applied to the lid tending to detach it, and wherein the latching of the said at least one lug on the second ridge is achieved, in the engagement position of the foldable skirt section in a local area only along the curved corner section of the second outwardly directed ridge, and with a latching covering between the mutually engaging faces of said at least one lug and of the second ridge, when viewed in a direction radial to the curved section of the second ridge, of larger dimension than the latching covering between the mutually engaging faces of the inwardly directed ridge and of the first outwardly directed ridge, when viewed along a direction radial to the curved section of the first ridge. characterized in that the first engagement portion of the container bearing the outwardly directed ridge extends and is elongated below the ridge, referred to as first ridge, and ends below the first ridge by a second ridge, also outwardly directed having a curved corner section, and wherein the foldable skirt section bears at least one lug, inwardly directed, which in the position of engagement of the foldable skirt section is able to latch below the second outwardly directed ridge of the first engagement portion, at least when a force is applied to the lid tending to detach it, and wherein the latching of the said at least one lug on the second ridge is achieved, in the engagement position of the foldable skirt section in a local area only along the curved corner section of the second outwardly directed ridge, and with a latching covering between the mutually engaging faces of said at least one lug and of the second ridge, when viewed in a direction radial to the curved section of the second ridge, of larger dimension than the latching covering between the mutually engaging faces of the inwardly directed ridge and of the first outwardly directed ridge, when viewed along a direction radial to the curved section of the first ridge.