Assembly formed by assembling two parts , in particular of a bodywork, of a motor vehicle comprising: - a first part ; - a second part , said first and second parts being assembled by clipping or snap-fitting; - a locking element intended to prevent any relative displacement between the first and second parts , said locking element being able to be displaced in rotation about an axis (ZZ') under the action of maneuvering means between an unlocked position, in which a relative displacement between the first and second parts is possible, and a locked position, in which it prevents any relative displacement between the first and second parts , characterized in that the locking element comprises: - a substantially cylindrical body which is centered on the axis (ZZ'), said body being partially housed inside a circular arc shaped cavity formed in a planar portion of the second part , said planar portion being aligned in a plane (P) which is perpendicular to the axis (ZZ'); - a pair of retaining fins , each of the retaining fins comprising an upper edge extending radially from a peripheral surface of said body and a lateral edge extending coaxially to said peripheral surface , one of the retaining fins forming with the body an annular groove configured such that, in the locked position of the locking element , it allows housing at least partially a retaining element of the first part and another of the retaining fins forming, with the body , an annular groove which is configured such that, in the locked position of the locking element , it allows housing at least partially a retaining element of the second part , said retaining elements having at least partially a profile which is substantially complementary to that of said annular grooves , and that, in the unlocked position of the locking element , said retaining elements are disposed outside said annular grooves ; and in that at least one of the first and second parts comprises a stop element which is configured such that, in the locked position of the locking element , it prevents any axial displacement of the locking element relative to the first and second parts . - a first part ; - a second part , said first and second parts being assembled by clipping or snap-fitting; - a locking element intended to prevent any relative displacement between the first and second parts , said locking element being able to be displaced in rotation about an axis (ZZ') under the action of maneuvering means between an unlocked position, in which a relative displacement between the first and second parts is possible, and a locked position, in which it prevents any relative displacement between the first and second parts , - a substantially cylindrical body which is centered on the axis (ZZ'), said body being partially housed inside a circular arc shaped cavity formed in a planar portion of the second part , said planar portion being aligned in a plane (P) which is perpendicular to the axis (ZZ'); - a pair of retaining fins , each of the retaining fins comprising an upper edge extending radially from a peripheral surface of said body and a lateral edge extending coaxially to said peripheral surface , one of the retaining fins forming with the body an annular groove configured such that, in the locked position of the locking element , it allows housing at least partially a retaining element of the first part and another of the retaining fins forming, with the body , an annular groove which is configured such that, in the locked position of the locking element , it allows housing at least partially a retaining element of the second part , said retaining elements having at least partially a profile which is substantially complementary to that of said annular grooves , and that, in the unlocked position of the locking element , said retaining elements are disposed outside said annular grooves ; and <EOS>