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Case

Cintrée Curvex compound-curved case

Probable

A tonneau case curved simultaneously along its length and across its width. The compound curvature propagates through the whole watch: the sapphire crystal, the dial and the movement mounting all have to follow it, and a doubly curved sapphire is an expensive component to produce.

Part reference

Brand
Franck Muller
Material
Steel, gold and gem-set executions
Introduced
1991

Documented variations

Classification

FactoryDocumented as shipped from the factory for this reference and period.PeriodNot original to this watch, but correct for its production period.ServiceFitted by the manufacturer's own service network. Not a defect.AftermarketThird-party part. Affects originality, not authenticity.ModifiedGenuine parts in a configuration the factory did not sell. Affects originality and value, not authenticity.CounterfeitDeceptive reproduction intended to pass as genuine.UnknownEvidence on file does not settle the question.
  • Genuine compound curvature with a matching crystal

    FactoryProbable

    Whole production

    Curvature visible in both axes from a profile view, with the crystal curved to follow the case and meeting the bezel cleanly all the way round. Judge from the side; from directly above the curvature is invisible.

  • Single-plane curvature with a flat crystal

    CounterfeitProbable

    Whole production

    The defining counterfeit. Correct from directly above and wrong from any other angle, which is why the standard seller's photograph conceals it. Asking for a profile view costs nothing and settles most Franck Muller questions before any other evidence is needed.

  • Replacement crystal that does not follow the curvature

    ServiceProbable

    Whole production

    A genuine case fitted with a generic curved or flat crystal, usually because a correct doubly curved sapphire was unavailable or too expensive at service. The watch is genuine; the crystal is wrong and will sit badly at the bezel edge. A service finding, and one that can be mistaken for the counterfeit pattern — check whether the CASE has compound curvature before condemning it on the crystal alone.

Open questions

OpenMissing imagesHigh

Photographic profile reference for genuine Cintrée Curvex curvature

What does the compound curvature of a genuine Cintrée Curvex look like in profile, across the different case sizes, and how does it compare against the single-plane counterfeits?

Scope The catalog nominates the profile view as the brand's primary check and then describes it in prose, which is weak for a judgement made by eye. A side-by-side profile comparison across case sizes would convert the strongest check on this brand from an instruction into a reference. Both sides are readily obtainable.

Documented on these references

Provenance of this record

Sources & Evidence

Secondary sourceCollector research

Research on Franck Muller counterfeits: case curvature, numerals and complication claims

Authentication services, dealers and collector communities

Accessed
2026-08-19

Cited for

This referenceProbable

Last verified: Not yet reviewed