Christine Nagel has a neat trick to demonstrate the surprises that await the perfumer when mixing scents. “Let’s do a little exercise,” says Nagel, sitting in her atelier on the top floor of the headquarters of Hermès’ perfume division in central Paris. Wearing no-nonsense blue jeans and a sand-coloured turtleneck, she passes me a small strip of scented paper.

“This is lime limette. It smells like a lime, but it’s a bit aggressive, like a cleaning product. And this,” Nagel says, handing me another strip, “is cinnamon. You can smell the cake, the spice. Cinnamon is warm; lime is cold. And if you do this,” she says, twirling the two sticks in front of my nose at once, “you smell Coca-Cola.”