It should be affixed to the leather body in such a way that is it sturdy and will not break off. The hardware on authentic Chloé bags should be heavy and of good quality. The hologram sticker will have a series of letters and numbers that will match the hologram sticker located on the authenticity card.
Note that on pre-loved bags, this sticker has sometimes come off over time, depending on how nicely the bag has been taken care of. There should be a hologram sticker present on the interior leather tab.
