Chanel introduced hologram stickers as an authentication tool in 1984. The sticker — a small metallic label inside the bag — contains a serial number that corresponds to an authenticity card provided with the bag. Authentic holograms shift colour and display a fine grid pattern when tilted under light.
The serial number on the hologram should match the number on the authenticity card exactly. The format of the number encodes the year of production — the number of digits and their arrangement changed over time, so a claimed 1990 bag with a ten-digit serial number is immediately suspicious.
Limitations
Hologram stickers are among the first elements counterfeiters attempt to replicate, and high-quality fakes can include convincing holograms. A genuine-looking hologram and matching card do not authenticate a bag — they're one element in a broader assessment. Never purchase a bag on hologram verification alone.