The present invention is directed to a packaging (1) comprising a container (2) with a container body (5), and a container opening (6) having an upper edge (7), and a closure (4) for closing said container, the container (2) and the closure (4) being made out of polyethylene terephtalate (PET), polyethylene naphtalate (PEN), or a combination thereof, said container and said closure comprising respectively first (8) and second (9) attachment means, characterized in that: (i) the attachment means (8, 9) are adapted in shape and size to cooperate with each other, and (ii) at least the second attachment means (8) is made of PET or PEN and adapted in shape and size to deform permanently by punching or rolling to link both attachment means, and create a permanent, preferably fluid-tight, arrangement between said container (2) and said closure (4).