Short answer
A replica Rendez-Vous Moonphase 240 stands or falls on the moon itself. If the aperture shows a flat printed disc that clicks forward once a day, you are holding a dress watch case with a costume complication inside. A good copy of this Jaeger-LeCoultre Rendez-Vous Moon runs a real 29.5 day moon disc, a mother-of-pearl dial that changes color as you tilt it, and a bezel where the stones are set rather than glued. The strap, clasp and box matter far less than those three things.
What the 240 in the listing means
It is not a Jaeger-LeCoultre reference number. Sellers use short codes like 240 to tag a case and dial combination, here the medium case with the moon aperture and a diamond bezel. Two listings carrying the same 240 tag can come out of different workshops with different movements. Treat the number as a shelf label, not a spec sheet. Ask for the case diameter, lug width and thickness before you compare prices.
The moon disc is the tell
Most buyers look at the dial first. I look at the moon window first, because that is where the money went or did not.
- Cycle length: a true moon phase travels through 29.5 days. If the disc steps once per day, it is a 31 day date wheel wearing a moon costume.
- Artwork: the original disc has a painted or engraved moon face over a graduated star field. Cheap copies use a sticker with a soft moon and no stars.
- Alignment: the moon should pass cleanly under the edge of the opening. Crooked travel or a visible gap around the aperture is common on budget builds.
- Setting: on a proper moon module you can advance the disc on its own, through the crown or a recessed pusher. If the moon only moves when the hands move, the complication is decorative.
Dial, bezel and case
Mother-of-pearl is hard to fake well. Real shell has depth: it goes from white to pink to green depending on the angle, and the grain is never uniform. Printed MOP patterns look flat and repeat. On the bezel, ask what the stones are. Cubic zirconia, moissanite and lab diamonds all appear in this tier, and they photograph differently under indoor light. Check the setting for even spacing, no glue haze around the stones, and no stone sitting at an angle.
On the case, the honest number to request is thickness. Moon phase modules stack on top of a base movement, which is why moon phase watches run thicker than time only watches of the same diameter. A copy that advertises the correct diameter but adds a millimeter or two of height will sit differently on the wrist. Crystal is the other quiet detail: sapphire with an anti reflective coating versus mineral glass is easy to spot once you tilt the watch under a lamp.
Movement and feel
Most of these builds use a Japanese automatic or an ETA clone with a moon module bolted on. Winding feel should be smooth with light resistance, not gritty. Give the rotor a slow turn near your ear: a faint whir is normal, a rattle is not. Power reserve on the common bases lands in the high 30s to low 40s of hours, so if a listing promises several days, that is a sign the seller is guessing.
Questions to ask before paying
- Send photos of the moon disc at three different phases.
- Confirm case diameter and thickness with calipers, not a tape measure.
- Name the movement, and confirm whether the moon phase sets independently.
- State the bezel stone type in writing on the invoice.
- Confirm a return window that covers a printed moon disc.
Bottom line
The Rendez-Vous Moonphase 240 is worth buying only when the moon disc is real and the dial is actual shell. Pay for those two things. Everything else on this watch is trim, and trim is easy to replace or forgive.