The Arceau L’heure de la lune watch offers a unique vision of Earth’s satellite with the simultaneous display of moon phases in both northern and southern hemispheres. Two mobile counters gravitate on a lunar, Martian or Black Sahara meteorite dial, revealing mother-of-pearl moons in step with an exclusive module, coupled with a Manufacture Hermès movement. Framed by a white gold or platinum case, the mechanics adopt a light, barely-there role. Meteorite inlaid with mother-of-pearl form a cosmos in which satellite dials float above hemispherical moons. These mischievous displays have swapped cardinal points, with the south above and the north below. A topsy-turvy direction inviting observers to lose their bearings, with their head in the stars.