A fake Ballon Bleu small (33 mm) gives itself away in four places: case proportions, the crown and its blue cabochon, the dial guilloche and printing, and the caseback engraving. A genuine 33 mm watch measures about 33 mm across and sits close to 10 mm thick, with a crown guard cut as a smooth curve into the case. Replicas miss thickness by 0.5 mm or more, print the dial too heavy, and set a flat glassy cabochon that sits proud of the crown.
Before you start
- A 10x loupe
- Digital calipers
- Photos of a known-genuine 33 mm Ballon Bleu from the same reference year
- Strong side light
Checks in order
- Measure the case across the bezel at 3 and 9 o'clock with calipers and confirm 33 mm plus or minus 0.2 mm.
- Measure thickness from caseback to crystal dome; a genuine automatic 33 mm sits near 10 mm, and a fake often reads 11 mm or more.
- Turn the watch on its side and check that the crown guard is a smooth curve cut into the case, not a block with a visible seam.
- Examine the crown cabochon under the loupe: it should be domed blue spinel with even color in a clean bezel, not flat glass with a bubble inside.
- Tilt the dial to the light and check that the Roman numerals are crisp with no ink spread and the guilloche rings stay continuous under the printing.
- Look at the blued steel hands for uniform blue with polished bevels; fakes show purple paint and rounded edges.
- Read the caseback engraving with the loupe: genuine text has sharp shoulders and even depth, and the serial is unique, not a repeated sample number.
- Match the caseback reference number to the correct size and movement, because fake sellers often mix 28 mm and 33 mm codes.
- Open the caseback only with the right tool, then compare the rotor engraving and movement finish with the calibre Cartier lists for that reference.
- Weigh the watch on a gram scale against a known 33 mm example; a light, hollow bracelet is a strong sign of a fake.
Replica vs counterfeit
A replica is sold as a replica and should carry that label in the listing, the invoice, and the packaging. A counterfeit is built to pass as genuine, and the checks above are what separate the two. If a seller claims genuine, pushes a bank transfer, and refuses a movement photo, treat the watch as counterfeit and walk away.
Common tells on the small model
- Crown cabochon too tall or too flat
- Thick ink at the Cartier signature
- Caseback screws that do not sit flush
- Bracelet links with sharp inner edges
- Serial card with the wrong font