On October 20, 1875, Henry James sailed for France. He embarked with the vague idea of establishing himself as a French novelist in a land he’d known and loved since childhood. But he was fleeing too from his native soil and, in particular, from Cambridge, Mass. For the young James — he was only 32 on that day — Cambridge epitomized everything that was narrow, provincial, and opinionated. Paris, by contrast, had long represented the cultural as well as sexual playground for straitlaced Americans. The city held out the promise of unexplored possibilities, both in life and in art. One of James’s fellow passengers on the Cunard liner Bothnia was Anthony Trollope. During the 10 days the crossing took, the two writers never became friendly. James admired Trollope’s methodical work habits — wherever he might be, Trollope wrote 2,000 words before lunch — but he held a low opinion of his fiction. For James, the future of the novel lay with the French. Despite the censoriousness of Cambridge he carried within him to the end of his days, he believed that Gustave Flaubert and his disciples — Emile Zola and Guy de Maupassant in particular — treated the novel as a serious art form, not as mere pennydreadful entertainment.

In his fascinating new study, “Henry James Goes to Paris” (Princeton University Press, 255 pages, $24.95), Peter Brooks, a professor of comparative literature at Yale, gives a detailed account of the year James spent there, a year that would shape him forever. Paris, though still recovering from the Franco-Prussian War and the horrors of the Commune, was vibrant. James, with his perfect command of spoken and written French, found most doors open to him. He gained admission to Flaubert’s inner circle. He chatted with the master and through him met everyone worth knowing. But he was suffered rather than accepted. No one who counted in Paris had the least interest in English literature, let alone in the work of an aspiring American novelist. Not only was Balzac, his lifelong idol, considered passé, but French writers were utterly ignorant of George Eliot, the paragon of English novelists for the young James. He had escaped the insularity of Cambridge only to come up against the monumental insularity of Parisian intellectuals.

James was lonely in Paris. He might enjoy affable afternoons in the company of Ivan Turgenev, an old friend of Flaubert, whom James termed “a magnificent creature,” or hear Giuseppe Verdi conduct his “Requiem,” but he remained excluded from more intimate contact with Parisian society. (He found himself reduced to dinners with his fellow Bostonian Charles Sanders Pierce, exiled to Paris and about as unlike a genius to James as could be imagined.) James’s own fussiness may have been partly to blame for his isolation. In a review he commented that “the French mind … has some surprisingly unpleasant corners,” and went on to remark that a novel by one of the Goncourt brothers was “intolerably unclean.” In another essay, he wrote that French literature generally resembled “little vases, skillfully moulded and chiselled, into which unclean things have been dropped.” The sense of “uncleanness” looms large in his opinion of things French. It was a subject surprisingly close to home.

As Mr. Brooks shows, James was at once priggish and “obsessed with sex.” While in Paris, he fell in love with Paul Zhukovsky, a Russian aristocrat and aesthete who would later become Richard Wagner’s favorite set designer. When he discovered that Zhukovsky was enjoying an openly homosexual liaison with a “sturdy, thickset” Neapolitan named Peppino, he confided to his journal, altering a line from Dante, “let us not speak of him, but look and pass on.” In his mature novels, from “The Portrait of a Lady” to “The Golden Bowl,” sexual betrayal constitutes the principal, and most excruciating, theme. Though he deplored the “brutal indecency” of Zola, he would learn from him, and especially from Flaubert, how to deal with such sordid topics with supreme obliqueness.

Mr. Brooks weaves together episodes from James’s year in Paris with his novels, from “Roderick Hudson” onward, to make plain how painstakingly James absorbed the lessons of the masters even as he seemed to repudiate them. Of Flaubert, James boasted (Mr. Brooks rightly calls it “an uppity judgment”) that “I easily — more than easily — see all round him intellectually,” but the lesson he took from him lasted a lifetime. In a brilliant analysis of “The Golden Bowl,” Mr. Brooks shows how Flaubert’s notion of “perspective” — what James would term “point of view” — germinated within him for decades before coming to fruition.

In the end James chose London, despite its “bad food,” over Paris. But in a sense, he never forsook France. He once advised a younger novelist to be “one of those on whom nothing is lost.” The phrase might have served as his own epitaph. To judge from Mr. Brooks’s account, there wasn’t a moment from James’s Parisian sojourn that wasn’t later turned to good, frugal New England use. Paris continued, in true Jamesian fashion, to “reverberate,” and not only in fiction. On his deathbed, in December 1915, after a second stroke, James dictated a note ordering the decoration of the Louvre and the Tuileries. He signed it “Napoléone.”

eormsby@nysun.com