The Bon Ton featured color illustrations produced by the pochoir (stencil) method. A description is here. Below are examples of Marty's work, some in pochoir, others using more conventional, less tedious methods.
The covers shown here are from French, British and American editions of Vogue. Haute couture was and is quite international.
Marty did posters for the Underground for a few years in the early 1930s.