It’s mid-morning in a glassed-in courtyard in the historic Marais district of Paris, and the Yves Saint Laurent marketing team’s sylph­like marketing reps—willowy and faultlessly soignée—are fanned out across the room’s limestone expanse. Each is wearing one or more items of YSL finery, including the silk safari dress, a 1968 creation that still looks fresh today. On practically every hand, one sees YSL’s signature gold rings with their chunky trademark stones. To underscore the morning’s well-orchestrated brand imprinting, all teeter elegantly on the iconic sky-high Tribute platform heels.

The Touche Éclat highlighter pen, another talismanic “jewel” of the YSL repertoire, is the focus of today’s gathering. The highlighter, which magically erases signs of fatigue, softens wrinkles and is a staple in every chic woman’s makeup bag, has been spun off into a foundation. More on that in a minute.

Used by stars from Salma Hayek to Demi Moore and still selling at a global rate of one every 10 seconds, Touche Éclat, even at the venerable age of 20, is the beauty icon that ticks all the boxes. It performs its difficult yet critical tasks of brightening complexions and banishing fine lines while simultaneously acting as a very covetable object. (In print ads, Jourdan Dunn and Ginta Lapina wield their gold Touche Éclat stylos as though they’re holding cigarettes.) And its success has inspired countless knockoffs, so many of which fail to make the grade. Some cheap imitators miss the mark completely and are just liquid concealers in sad white plastic cases—no luminosity, no magic. “Touche Éclat doesn’t cover; it illuminates,” says Lloyd Simmonds, creative director of makeup for YSL. “Wherever you want a bit of a lift, it gives a little light.”

For any woman who has joked that she would happily cover her entire face with Touche Éclat the morning after a late night, the idea of a companion foundation is surely the beauty world’s version of catnip. The YSL team thought so too. “Touche Éclat is the number one concealer worldwide,” notes Isabella Weinstabel, inter­national marketing director for YSL Beauté. In other words, spinning the brand off into a foundation is what the French might call a case of n’hésitez pas (no-brainer).