Bertrand joins the National Guard during the Franco-Prussian War, doing little fighting and finding love from a girl who volunteers at a canteen, the beautiful and wealthy Sophie de Blumenberg.

Sophie, a masochist and obsessed with death, helps Bertrand avoid the violent effects of his transformation by allowing him to cut into her flesh in order to suck her blood.

Aymar transfers Bertrand to an asylum after the reactionary Versaillists have retaken Paris, with great loss of life among the Communards, who are executed en masse.

"[6] The novel draws inspiration from the true story of the French general, Francois Bertrand, infamous as "the necrophilic sergeant" or "the vampire of Montparnasse".

Between 1848 and 1849, Bertrand experienced brutal fits that led to acts of necrophilia and cannibalism in several French cemeteries, particularly in Pere Lachaise and Montparnasse, both necropolises located in Paris.

The account of Francois Bertrand's actions was chronicled in the treatise titled The Book of the Werewolves by the English scholar Sabine Baring-Gould, published in the year 1865.

It is rumored that Endore, suffering under the impact of the Great Depression, sold the manuscript outright to Farrar & Rinehart for a flat fee, thus receiving no additional royalties from its subsequent success.

Given that Endore's next novel, Babouk (1934), was published by the leftist Vanguard Press, this story could have merit, although that work's revolutionary Haitian subject matter might simply have proven too controversial for Farrar & Rinehart.

Anthony Boucher and J. Francis McComas, notable sci-fi and mystery writers in the 1940s and 1950s, described The Werewolf of Paris as a "superb blend of fantasy and psycho-pathology and history.