A little bit of phantasmagoria and a lot more "And-then-he-fucked…" grungy glamour, Gainsbourg: A Heroic Life is at its best when its mythologizing is carnal and infused with cabaret, and not making the inflated claim of its title. Writer-director Joann Sfar, a comic artist adapting his own graphic novel's version of the life of French singer-songwriter Serge Gainsbourg, generally eschews staples of the musician biopic like stage-performance recreations and studio-session drama. His focus is first on the artist as a boy in Nazi-occupied Paris, born Lucien Ginsburg (Kacey Mottet Klein), wearing a yellow "Juif" star with poise and already cultivating his interests in art and women, and then how he fashioned himself into the roguish seducer personified in the 1960s hit-making persona of salacious Serge (Eric Elmosnino, a near-lookalike with the requisite lascivious panache and curled lip).
In Sfar's vision, Gainsbourg is mentored from his salad days as a thwarted painter and piano-bar tinkler by a hawk-nosed, bat-eared alter ego, "La Gueule" (Doug Jones beneath prosthetics), a gargoylish double of his own "ugly mug" who spurs him to start writing his own dirty ditties for a comedic nightclub troupe, and then to leap at his big break writing for and bedding chanson singer Juliette Gréco (Anna Mouglalis). As with many of the figures populating Gainsbourg in cameo and substantial roles, Gréco now means little outside of France; even Sfar's subject, despite his devoted contemporary global cult, is a marginal figure to most audiences, and a quasi-absurdist bio that emphasizes the intimate over the musical isn't likely to win converts.
But Sfar's agenda isn't to proselytize for unappreciated genius. He primarily delights in Gainsbourg's infatuation with himself, and his sozzled romanticism in courting beautiful women as collaborators and lovers. Even Serge's papa, a pianist who leavens praise for his son with severe assurances that "popular music is merde," does a victory dance when he learns his boy has seduced movie queen Brigitte Bardot (Laetitia Casta). Sfar is inspired by the pairing too; when Casta, wrapped in a bedsheet, cavorts beside Elmosnino's keyboard as he bangs out "Comic Strip" in their love nest, it's Gainsbourg's closest brush with a production number. And when Serge courts the moody young British actress Jane Birkin (the late Lucy Gordon), finally winning her heart with a drunken encomium on the banks of the Seine before passing out in her lap, the gesture stands in for the enigma of love. We don't comprehend his passion for Birkin, just know that she's soon recording a hot-breathing, orgasmic duet ("Je t'Aime…Moi Non Plus") that Bardot's husband vetoed for her. Lust, music, careerism—homely Jewish boy makes good.
Handsomely mounted and shot with an eye for nocturnal Parisian mystery by Guillaume Schiffman, Gainsbourg somewhat mercifully peters out after the grande scandale of the provocateur's reggae version of "La Marseillaise," which earned him the wrath of French patriots. The end of his marriage to Birkin is abruptly treated in a single, armed tantrum before the kids, and his last wife is portrayed as a youthful cipher. Part of Serge's posthumous showbiz currency is, of course, that he sired a film star, and Charlotte Gainsbourg was slated to portray her father in an earlier conception of Sfar's project. But the songwriter's persona doesn't seem a fortuitous match for I'm Not There-style pomo refraction; Serge was all there, and Gainsbourg is content to score his sensual and artistic conquests, and on occasion captures his brazen prurience with the theatrical frivolity of Serge's self-conscious pucker clamped on a cigarette or an A-list paramour.