Short Answer
A replica Duomètre Quantième Lunaire is worth buying when three details hold up: a 40.5 mm case footprint, a dial layout that matches the Dual-Wing design, and a moon phase that stays on cycle. Buyers who skip those checks end up with a watch that looks correct in a listing photo and falls apart under a loupe. The inspection below takes about twenty minutes and covers the failures that show up most often on this reference.
Why This Reference Is Hard to Copy
The Duomètre line runs on a Dual-Wing architecture: two gear trains and two barrels inside one movement, with one barrel feeding the timekeeping train and the other feeding the complication. On the Quantième Lunaire that shows up as two power-reserve indicators on the dial and a moon phase driven by its own energy supply. A replica cannot reproduce that engineering at scale, so most versions use a single movement with decorative subdials. Knowing the difference tells you what you are actually paying for and which claims deserve scrutiny.
Before You Start
- Reference photos of the genuine 40.5 mm model, dial side and caseback
- A digital caliper, or a seller willing to send measurements in writing
- A loupe or a phone macro lens
- Written confirmation of the return window and refund terms
Inspection Steps
- Ask the seller for the case diameter across the bezel, the lug-to-lug span, and the total thickness, then compare those numbers with published specifications.
- Weigh the watch on a kitchen scale and compare the figure with the genuine weight range for a steel case on a leather strap.
- Place the dial photo beside a reference image and check the position of each power-reserve arc, the moon aperture, the date display, and the running seconds.
- Confirm that both power-reserve indicators move when you wind the crown, and note which direction each one travels.
- Wind the watch fully, set it down, and record the time after 24 hours to see how far the rate drifts.
- Set the moon aperture to a full disc, photograph it, then repeat the photo seven days later to confirm the disc advances roughly a quarter of a cycle.
- Advance the hands past midnight and watch whether the date changes on its own without the moon disc jumping.
- Inspect the subdial hands at magnification to check that they point at the markers rather than sitting off center.
- Turn the watch over and read the caseback engraving, including the calibre number, the reference, and the font weight of each line.
- Check the movement finish through the sapphire back for Geneva stripes on the bridges, blued screws, and clean perlage on the base plate.
- Press each corrector and confirm it returns flush to the case with no grinding or sticking.
- Flex the strap and close the clasp a few times to test the spring bar fit and the folding mechanism.
Rejection Signals
- Case diameter off by more than 0.3 mm from the stated size
- A moon disc that runs on a printed 29.5-day cycle and drifts within two weeks
- Power-reserve hands that are painted on rather than geared
- Rotor noise loud enough to hear from arm's length
- Engraving that is stamped shallow or filled with paint
- A seller who refuses measurements, macro photos, or a return window
Price and Expectations
Well-built replicas of this reference sit in the mid range of the replica market, above generic moon phase models and below hand-finished custom builds. That price buys an accurate case profile, a sapphire crystal, a decorated automatic movement, and a moon phase that tracks within a day per month. It does not buy twin barrels or a genuine Dual-Wing gear train, and no honest seller will claim otherwise. Treat any listing that promises the real movement architecture as a warning sign.
After Purchase
Keep the watch away from magnets, wind it at the same time each day, and use the correctors only when the hands are clear of the changeover window around midnight. Have a local watchmaker check the gaskets once a year if you wear it near water, since replica case seals age faster than the movement inside them.