CALAIS, France — The clang of giant weaving looms ricocheted across a cavernous factory one recent afternoon at Desseilles Laces, one of the oldest lace makers in France. A handful of workers flitted among the machines, guiding gossamer threads into a floral confection destined for luxury lingerie and couture dresses.

The halls here, and at hundreds of lace factories around Calais, were once thick with employees. But as competition from countries with cheaper labor costs buffeted France, waves of layoffs swept through this working-class town on the edge of the English Channel.

Today, fewer than 300 employees remain at just three factories — Desseilles, Noyon Dentelle and Codentel — a fraction of the 30,000 whose livelihood depended on lace less than two generations ago. Around Calais, the hulking brick skeletons of abandoned lace factories cast shadows over modest, low-slung houses. And Desseilles was recently taken over by a Chinese investor, drawing laments that a crown jewel of the industry had fallen into foreign hands.