A case assembly, rotating or non-rotating, containing a cosmetic product such as lipstick, and a closure cap associated with that case by way of complementary attachment and release mechanisms, wherein the rotating case as well as the attachment and release mechanisms for the cap are completely integrated into the latter; and the attachment and release mechanisms are constituted by a hollow piston, movable in translation, disposed concentrically in the bore of the cap and capable of sliding therein, the hollow piston itself having a bore in which the case carrying the lipstick is housed and secured at one end by way of a removable attachment mechanism, the piston furthermore having a locking and unlocking mechanism interposed between the piston and the cap and acting in one direction or the other by axial pressure exerted simultaneously on the cap and on the visible surface of a base of the integrated case, which base is in contact with the piston, so as to cause release, with respect to the cap, of the piston and hence of the case which is secured therein, and make the base of the case graspable by a user in order to remove it.