Abdellatif Kechiche’s Blue is the Warmest Colour was nominated for a BAFTA and won Palme d’Ors for its two leading actresses, yet it’s also steeped in controversy. Lengthy and explicit sex scenes, and allegations from cast that working conditions bordered on abusive, combined with a slow pace and lengthy running time, provide plenty of debate fodder.

On the surface, this is the straightforward story of Adele (Adèle Exarchopoulos), a beautiful and bookish teenage girl, and her coming of age. Adele’s world revolves around the usual preoccupations: boys, friends and school. But it’s obvious that Adele, despite her popularity, doesn’t quite fit in. When she randomly passes the blue-haired and arty Emma (Léa Seydoux) on the street, Adele is magnetically drawn to the older girl. When they embark on a romance, Adele begins the slow transition into adult life with all of its pleasures and responsibilities, loneliness and regret.

Leaving aside the gender of the two protagonists, Blue is the Warmest Colour is a very tender, naturalistic tale of blossoming romance, self-exploration and the personal growth that often accompanies the pain of loss. Viewers are brought into this sometimes claustrophobic intimacy via camera work that lingers on the corner of a smile or the curve of an inner arm, much as a lover’s gaze would do and touches of blue remind us constantly of Emma’s importance in Adele’s life.

For a tale so determinedly grounded in realism, the much-discussed sex scenes are the film’s Achilles heel. There is sufficient artistic merit to avoid the label of pure pornography – but only just. The main issue is the confidence of the supposedly virginal Adele and the lingering camera that conveys authenticity in other scenes seems rather more voyeuristic here. Blue is the Warmest Colour is, for the most part, an admirably authentic tale of a seminal love affair and that harsh borderland between adolescence and adulthood, but its failings may inspire some viewers to explore the rest of the genre.