Jules Louis Félix Roy, who adopted the name Sylvain Sauvage when he moved to Paris to acknowledge his roots in the wild mountains of the Jura in eastern France where he grew up, was planning to limit his artistic skills to architecture like his father. But like his father Alphonse he had an artistic streak. After leaving school in the small town of Baume-les-Messieurs, in 1910, as had his father and older brother Paul, he went to Paris to study architecture at the École des Beaux-Arts. Studying under the prize-winning architect Eugène Chifflot, he graduated with honours in 1913.

Then came the war, and he was mobilised as a nurse at the hospital of Lons-le-Saunier near his childhood home. In 1917 asked the École des Beaux-Arts for a certificate to be assigned, like his brother, in the Engineer Corps, and was decorated with the Croix de Guerre.

Not having been able to complete his architectural studies, he made the decision to study illustration and engraving under the tutelage of Charlotte Grappe (1890–1930), a fashion designer who had trained at the School of Decorative Arts. Félix/Sylvain and Charlotte married in 1920, and they had a daughter, Monique, who also became an artist.

His first major artistic project was to illustrate the amorous adventures of Casanova, which started as a self-published portfolio and later as a book in collaboration with Paris publisher Paul Cotinaud. Une aventure de Casanova, which the demanding artist insisted should be produced to perfection, resulted in a range of different versions including some complex colour work. It is probably no coincidence that Sylvain Sauvage’s main body of erotic illustration coincided with his early years of marriage.

He entered the 1925 Paris International Exhibition of Decorative Arts in Paris on the advice of his architect friend Eric Bagge, and was pleasantly surprised at the positive response. Bagge taught at the prestigious Paris École Estienne, or to give it its full name l’École Supérieure des Arts et Industries Graphiques, of which Sauvage was to become Principal from 1934 until his death.

Charlotte died early in 1930, and in November of that year Sylvain married Xénie Ordowsky de Tanaïevsky, the daughter of a doctor exiled with her family during the Russian Revolution.