“I do think it’s a bit of a myth. I think we’re all just products of lots of different cultures,” says Seward, noting that even her friend Inès de la Fressange, a global paragon of French style, is actually half Latin American.

Seward goes even further in her new book, “Le guide de la gentlewoman” (“The Gentlewoman’s Guide”) due to be published by JC Lattès on Wednesday. “The Parisienne does not exist,” she declares in the autobiographical volume, which consists of alphabetical entries covering everything from style icons to surgery and selfies.