Abstract: The device comprises a removable cap (20) for closing the neck of a receptacle (3), and a peelable membrane for hermetically covering the lip of the neck. In order to guarantee good sealing of the receptacle when it is reclosed with the cap, the peelable layer of the membrane is adapted to cover only an inner zone (61) of the lip (6) of the neck (3), the cap being provided internally with a skirt (24) for bearing in leaktight manner against an outer zone (62) of the lip that is distinct from the inner zone (61), and said skirt is plastically deformable between a generally cylindrical configuration and a flared configuration, the inside face of said skirt presenting a transmission surface (244) for transmitting a bearing force (F2) associated essentially with co-operation between the skirt in its flared configuration and the lip of the neck.