For 16 years, Guy Sémon worked on some of the most technologically advanced wristwatches ever produced, including the TAG Heuer Mikrogirder and the Zenith Defy Inventor. But the horology world hasn’t heard from him for the last four years.

In a recent interview, he said that was because he had been developing his own brand, scheduled to debut next year, and specializing in watches that would be “the most original, the most precise and absolutely uncopyable.”

Mr. Sémon, 61, who was a French Navy pilot before completing his Ph.D in physics, began his career in military aeronautical engineering. He became involved with watches after a chance meeting in 2004 with Christoph Behling, the British designer commissioned by TAG Heuer to create a timepiece with a belt-driven movement.

“The watch didn’t work when it was first presented,” Mr. Behling said. “Guy came in to make it work in reality. He had a very different approach because he’s not a trained watchmaker honoring the past. He is a mathematician and a scientist, but he had a love for what watchmaking represents. He was interested in how far you can push something.”

The belt-driven watch was the Monaco V4, introduced as a concept piece in 2004. Mr. Sémon developed a functional version in 2006 and, two years later, became the head of the brand’s research and development division. From 2010 to 2012, he presented a series of chronographs, or stopwatches, that measured ever-smaller intervals by purely mechanical means, culminating in the Mikrogirder, a watch capable of splitting time to five 10,000ths of a second, a record that still stands.

He then went on to lead the LVMH Institute, a research center that provided high-tech movements to the LVMH watch brands TAG Heuer and Zenith, and left in 2020 when the institute was dissolved.