In 1979 Paris, Anne (Vanessa Paradis) runs an independent film studio making gay pornography. When a masked assailant begins stalking the city’s gay community, violently murdering Anne’s actors one by one, she is drawn into tracking the killer down before they come for her as well.

Yann Gonzalez’s Knife + Heart is a lurid, pulpy affair, both stylish and deeply tacky at the same time. While a French production it riffs quite deliberately on old Italian ‘giallo’ films: colourful and bloody thrillers with a healthy dose of sex and violence. Despite taking considerable inspiration from the style, it approaches it in a very self-conscious way. Knife + Heart, it seems, wants to wallow in giallo while simultaneously mocking it. It indulges in excesses of blood, nudity, and violence but also seems to invite an amused frivolity from the viewer. It has the structure of a murder mystery but the soul of a comedy. Altogether it is a rather strange piece that manages to intellectually fascinate more than it emotionally engages.

Vanessa Paradis dominates the film as Anne. Rejected by her ex-girlfriend, she is living a brittle and self-destructive life. She drinks to excess, clings hopelessly to a potential reconciliation, and resorts to self-obsessive moping for much of the film. Certainly there are no attempts to round off the character’s less acceptable facets: Anne is an emotional mess and neither character nor filmmaker are looking for sympathy.

There are some proper gems among the supporting cast, particularly Nicolas Maury as Anne’s overly supportive and enabling right-hand man Archibald. It is a finely-tuned performance, staying unobtrusively in the sidelines but presenting brilliant character work at the same time.

Electronic band M83 provide the film’s excellent musical score, whose synth-sounds provide an eerie and unsettling effect. To some extent the score manages to paper over the film’s main fault, which is a constant struggle to find a consistent tone. More jovial and humorous scenes jar badly against the graphically violent murders, which puncture the otherwise frivolous tone with an unsubtle and repellent sense of sexual assault and provocation (the killer has converted a sex toy into a spring-loaded knife, for example). There is tone but not suspense: the result is something that inspires distaste rather than tension. It all works better the lighter it gets; by the end the more serious aspects of the production begin to feel like dead weight. There is a mystery and a subsequent reveal, but they feel rote and formulaic compared to the more inventive design and atmosphere. The film’s scenes of Anne’s in-production films are particularly effective: presented in an unexpectedly coy fashion, they tease and amuse rather than confront. It pushes the contract with the film’s violence even further.

Perhaps this is Gonzalez’s intention; if so, it does not appear to work very well. Knife + Heart feels like a picture at war with itself. It is rich in potential and when it works it sings. When it stumbles, it can oftentimes wind up actively unlikable.