The invention relates to a closure device (1) for attaching to a packaging container (2), the packaging container (2) being closable by the attached closure device (1) such that it can be reclosed but cannot be opened by children. The invention is characterized in that the closure device (1) is made in a proportion of at least 70% of a paper-based material and comprises a tab receptacle (4) delimiting a receiving space (6),and an
insertion tab (5) having a hook element (7), wherein: the
insertion tab (5), in order to close the closure device (1), can be inserted in the receiving space (6) of the tab receptacle (4); in the receiving space (6) an edge (9) is provided with which a free end (8) of the hook element (7) of the
insertion tab (5) lockingly engages when the insertion tab (5) is inserted in the receiving space (6) so that it is possible to withdraw the insertion tab (5) from the receiving space (6), in order to open the closure device (1), only when simultaneously pressure is applied to the hook element (7) in order to release locking; for this purpose, an opening (21) is formed in a wall of the tab receptacle (4) near the edge (9), through which opening pressure can be applied to the hook element (7), which is inserted in the receiving space (6), in such a way that the free end (8) of the hook element (7) is released from locking. The invention also relates to a packaging (100) comprising a packaging container (2) having a removal opening (3) and a closure device (1) of the above type.