The Berneron Mirage 38 Sienna, reference 3438MS.G02, is an asymmetric, time-only dress watch from the young Swiss independent founded by Sylvain and Marie-Alix Berneron. Its 18k yellow gold case measures 33.5 mm wide, 37.5 mm long and 7 mm high, with a lug-to-lug length of 42 mm, and combines satin-brushed and polished surfaces. Water resistance is 3 bar (30 m). The top crystal is coated hesalite and the caseback is sapphire. The dial is also made of 18k yellow gold, satin-brushed and polished, with sienna-coloured markings laid out in sectors, a custom numeral font, a small seconds sub-dial and gold hands. The shaped, manual-wind calibre 233 was developed for the watch with Le Cercle des Horlogers. It is 2.30 mm thick, has 135 components and 17 jewels, uses 18k gold plates and bridges, runs at 3 Hz (21,600 vph) and shows hours, minutes and small seconds.

The core idea of the Mirage is that the movement dictates the case: the outline of calibre 233 sets the irregular shape of the case and dial. Berneron introduced the white gold Prussian Blue (3438MS.G01) and yellow gold Sienna versions in November 2023 and later added a smaller Mirage 34 with a new 2.15 mm calibre 215. Crown, buckle and spring bars are all 18k gold, and the Sienna is worn on a grained reddish-brown calfskin strap. Production is limited to 24 Mirage 38 pieces per yearly allocation, split between the two metals. The launch price was CHF 55,000 excluding VAT; later reports give CHF 61,000 excluding taxes.

The Mirage made Berneron one of the most discussed new independents. Monochrome described it as truly mesmerising and praised the transparency about the movement’s development, while admitting the unconventional look takes a moment to get used to. Watchonista noted that the watch appeared on many 2024 best-of lists and attributed its success to the trend for shaped watches and the shape-driven movement. The Sienna won the Audacity Prize at the 2024 GPHG. At Phillips’ New York Watch Auction XIII, a Mirage 38 Sienna sold for USD 190,500 against an estimate of USD 40,000 to 80,000. As of October 2026 the Mirage 38 Sienna remains in small-series production, with allocations reported as spoken for through 2027.