Short answer
Cartier does not list a watch called Rotonde 4200. Rotonde casebacks carry references that start with W, followed by digits. The number 4200 in online listings points to a 42 mm case diameter, and sometimes to a movement the seller cannot name. No Cartier catalog page uses 4200 as a model number. A listing with that number describes a replica, not a watch from the brand.
What the genuine Rotonde line is
The Rotonde de Cartier is a round-case dress watch family from Cartier, owned by Richemont. Production covers time-only, chronograph, and high-complication pieces. The 42 mm versions use in-house automatic calibres from the 1904 MC family with a 48-hour power reserve. Cases come in steel, 18k pink gold, and 18k white gold. Most references use sapphire crystal on the front and the back. The caseback is engraved with the reference, the serial number, and the caliber.
How counterfeit Rotonde watches differ
- Case metal. Replicas use 316L steel with gold plating. A plated case weighs 30 to 50 g less than a solid 18k gold case of the same size.
- Movement. Most fakes carry a Chinese automatic or a quartz module. The rotor has no Cartier engraving. Many fakes beat at 21,600 vph. The Cartier 1904 MC beats at 28,800 vph.
- Dial printing. Roman numerals on fakes are too thick. The Cartier script sits off center on many units.
- Caseback. Fake engraving is laser cut and shallow. Missing serial numbers and repeated serial numbers are frequent.
- Price. Counterfeit Rotonde listings run from about $60 to $400. Used genuine 42 mm Rotonde watches in steel sell in the $5,000 to $9,000 range.
Legal status in the United States
Trafficking in counterfeit goods is a federal crime under 18 U.S.C. § 2320. A first offense carries up to 10 years in prison. U.S. Customs and Border Protection seizes counterfeit watches at ports of entry, and the agency states that counterfeit goods are subject to seizure even when imported for personal use. Resellers can face civil claims from Richemont.
Checks a buyer can run
- Request a caseback photo. Read the reference. Rotonde references start with W.
- Request a movement photo. Real 1904 MC movements show Côtes de Genève finishing and a signed rotor.
- Weigh the watch. A 42 mm gold Rotonde runs over 100 g with the strap. A plated fake sits under 80 g.
- Get the serial number and confirm it with Cartier client service.
No public Cartier document assigns the number 4200 to a Rotonde reference. Documents that show it come from sellers.