The invention relates to a method for manufacturing packs (1) characterized in that it comprises steps according to which: a packaging film is unwound; a first gusset is formed on the unwinding packaging film; a second gusset is formed on the unwinding packaging film, the second gusset being formed on the same edge of the unwinding film as the first gusset (3), said second gusset being associated with a closure assembly to form an opening indicator.