SAINT-OUEN-L’AUMÔNE — Trained in boilermaking in Poland, Witold Okraska discovered France at the same time as La Cornue, in 1990, when he was 18 years old. Hired as a sheet metal folder, Okraska became head of the workshop in 2015. Today, under his leadership, nearly a dozen metal craftsmen cut, bend and weld the stainless steel plates that are used as the front of the cooking ranges. A far cry from mass production, each range is unique. “I sometimes work to a tenth of a millimeter,” says Samuel Dias, one of the precision folders. Working nearby, the welders have the same attention to detail. …