Short answer
A fake Breguet Classique Ultra Thin copies the Breguet Classique 5157. The genuine watch has a 38 mm case, a 5.4 mm case height, 18k gold, a hand-guilloché dial, and calibre 502.3. Copies sell for $150 to $900. Most measure 8 mm to 9.5 mm thick. No copy uses a Breguet movement. Trafficking in counterfeits is a federal crime in the US under 18 U.S.C. § 2320.
What the real 5157 is
Breguet dates to 1775 in Paris. Abraham-Louis Breguet patented the tourbillon in 1801. The Classique line is the dress line. Reference 5157 is the ultra-thin automatic in that line. Breguet lists a round case, a fluted caseband, welded lugs, and a sapphire caseback. The dial carries engine-turned guilloché, cut on a rose engine. The hands are blued steel with open tips, known as Breguet hands. The numerals are Roman. The crystal is domed sapphire.
Where copies diverge
- Case height. Genuine is 5.4 mm. Copies run 8 mm to 9.5 mm. The movement drives the extra height.
- Movement. Genuine calibre 502.3 is an ultra-thin automatic. Copies use a Miyota 9015, a Seagull, or an Asian ETA 2892 clone. All are thicker.
- Dial. Guilloché on the genuine dial is cut on a rose engine. Copies use laser cutting or stamping. Line edges look shallow under a loupe.
- Case metal. Genuine is solid 18k gold with a French hallmark. Copies are brass with 3 to 5 microns of plating.
- Weight. Solid gold cases run heavier than plated brass. A kitchen scale shows the gap.
- Engraving. Caseback text, serial numbers, and logo spacing differ from Breguet tooling.
Price tiers seen in the market
- $150 to $250. Quartz or basic automatic. Mineral glass. 9 mm or more thick.
- $300 to $550. Automatic with a Miyota or Seagull movement. Sapphire glass. 8.5 mm to 9 mm.
- $600 to $900. Sold as "super clone" or "1:1". Decorated rotor and better dial printing. Still above 6 mm.
Some sellers claim 6.5 mm. Measurements from buyers vary. No public test has shown a copy at the 5.4 mm figure. Treat that number as unverified.
US legal position
Counterfeit goods cannot be imported into the United States. CBP can seize and destroy shipments. The buyer gets no refund and no return of the goods. Selling or trafficking counterfeits carries a prison term of up to 10 years for a first offense under 18 U.S.C. § 2320. The OECD reports that watches rank among the most traded counterfeit categories by value.
Checks on a watch in hand
Measure case height with calipers. Weigh the head in grams. Look for a 750 hallmark or an eagle head stamp. Inspect guilloché lines at 10x. Read the caseback font. A Breguet movement shows the calibre number and maker name on the bridges.