The short answer
On a replica Breguet Classique moon phase, judge the moon aperture before anything else. A real moon phase uses a geared disc that completes one cycle in roughly 29.5 days. Most cheap replicas fake it with a 24-hour day/night disc that turns once a day, or a printed wheel glued to the hour hand. If the moon moves through the window in a day, that is the whole watch. If it tracks the lunar month, you can start looking at the dial, the case and the movement.
Why the moon phase is the hard part to copy
The moon is the one complication that cannot be hidden behind good finishing. It needs a separate gear train, a corrector, and enough depth in the case for a disc. That is why so many replicas either skip it or fake it. I look at the aperture itself. On the genuine Classique references, the moon sits on a blued or silvered disc with a gold moon face and a star field, set under a slightly recessed window. Clones usually print the stars flat and leave the disc sitting proud of the dial.
Dial details that separate good from bad
- Guilloche: the engine-turned pattern should stay sharp under raking light, with even concentric rings. Stamped foil looks soft and the pattern fades at the edges.
- Hands: Breguet hands are blued steel with an eccentric hollow moon tip. Cheap versions are painted blue and too thick at the point.
- Signature: it should be engraved into the dial, not screen printed on top of it. The secret signature is a nice extra, but its absence is not always a deal breaker on a replica.
- Numerals and subdials: check that the moon aperture is centered on the vertical axis and that the outer track is not squeezed by a mismatched dial blank.
Case, lugs and the fluted band
Breguet cases have a finely fluted caseband, the coin-edge ring, and welded lugs that flow into the band with no seam. Replicas often use a coarse milled ring, or leave the band smooth because the case is too thin to cut. Size matters too. The Classique moon phase references sit around the 39mm mark, so a 41mm or 42mm "Classique" is a different watch wearing a familiar name. Ask for a caliper photo, not a wrist shot.
Movement and the back of the watch
A sapphire caseback is your best tool. Look for a real module under the dial, not a disc bolted onto the hour wheel. Most replicas run a modified ETA 2824 or 2892 pattern, or a Chinese equivalent with a moon module stacked on top. That stack adds thickness and it changes how the crown feels. Wind it and set the moon with the corrector. Genuine moon phases have a dedicated pusher or recessed corrector. If the only way to move the moon is by resetting the time forward, it is decorative.
Questions worth asking a seller
- Does the moon complete a cycle in about 29.5 days? Ask for dated photos across three or four days.
- What is the exact case diameter and thickness in millimeters?
- What movement base is used, and is the moon on its own gear train?
- Are the engravings on the caseback crisp, and do they match the reference shown on the dial?
Price and the legal reality
Prices for a moon phase clone run well above a basic three-hander because of the module, and the gap between a good one and a bad one is wide. Be clear about the trade: no Breguet warranty, no authorized service, and no resale value. In the United States, importing counterfeit goods is illegal even for personal use, and Customs can seize and destroy the package. Reselling one is trademark infringement. Treat it as a personal purchase with real risk attached, not an investment and not a substitute for the genuine article.