Short answer

A replica Ballon Bleu 24mm is a counterfeit Cartier Ballon Bleu with a case listed at 24 mm across. Cartier does not list a 24 mm Ballon Bleu. The smallest size in the current line is 28 mm. Listings that use the 24 mm number describe a smaller aftermarket case, quartz in most units, built for a wrist of roughly 12 cm to 14 cm. No genuine 24 mm reference number is documented.

Real Ballon Bleu sizes

Cartier lists the Ballon Bleu de Cartier in 28, 33, 36, 40, 42 and 44 mm. The 28 mm model (ref. W69010Z4) runs a quartz movement. Models at 33 mm and above run automatic movements. Case metal is steel, yellow gold, rose gold or white gold. A blue spinel cabochon sits in the crown guard. The dial sits under a sapphire crystal domed on both faces. Cartier registered the Ballon Bleu shape in 2007.

What a 24 mm replica is

  • Case: 24 mm to 25 mm across, crown excluded.
  • Movement: quartz, often a Japanese or Swiss blank. Automatic movements at this size are rare.
  • Weight: 40 g to 60 g on a leather strap. A genuine steel 28 mm model weighs more.
  • Crown: the blue cabochon is glass or plastic on most units, not spinel.
  • Strap: 12 mm to 14 mm lug width. Genuine Cartier 28 mm straps use 15 mm lugs.
  • Crystal: mineral glass on low-end units, sapphire on the better ones.

Points that decide quality

  1. Case thickness. Slim cases near 8 mm match the real proportions. 10 mm or more reads as bulk.
  2. Cabochon color. Spinel is deep blue with no bubbles or seams.
  3. Dial print. The Cartier name and Swiss Made mark stay crisp at 3x magnification.
  4. Guilloche pattern. Even line spacing, no blur at the center.
  5. Hands. Blued steel look, no flakes, no bent tips.

US legal status

Replica watches are counterfeit goods. Import into the United States is barred by 19 U.S.C. 1526. Trafficking in counterfeit goods carries criminal penalties under 18 U.S.C. 2320. US Customs and Border Protection seizes counterfeit watches and destroys them. Resale brings separate civil liability to the trademark owner.

What is not known

No public source confirms Cartier ever made a 24 mm Ballon Bleu. Movement suppliers for 24 mm replicas vary by batch and are not disclosed. Weight and case figures come from seller listings and are not verified by a third party. Prices change by seller and are not listed here.