The marvellous Adèle Haenel plays busy young doctor Jenny, who one night fails to answer the door after-hours at her practice only to find the next day that the girl who rang the bell has been found dead. Racked with guilt, Jenny seeks to find out more about the girl who the police have drawn a blank on. Her guilt is further compounded by the fact that she didn't open the door due to the fact that she was in the middle of an argument with a medical student doing an internship, Julian (Olivier Bonnaud). Julian seems to have taken a dressing down about becoming emotional so badly that he's now willing to quit medicine altogether. It's unclear whether the relationship between the two has ever been something other than professional, but Jenny spends an inordinate amount of time trying to contact him and even drives out to his village to see if she can persuade him to reconsider his decision.
In the meantime, Jenny drives around from patient to patient showing a photograph of the murdered girl. Fortunately for her and the Dardennes, several of her patients or their relatives have relevant information. The naturalistic direction evokes something of a documentary style but the contrivances of the plot are thoroughly artificial. In addition, the rhythm of 'something positive and then a little bit of danger, something positive then a little bit of danger' becomes hugely repetitive. Another aspect that challenges the vaunted realism is the way people behave differently in Dardenne films to reality. As part of her expiation, Jenny passes up a lucrative job and informs her new boss at the last minute. They've already had a welcoming party for her and unveiled a new office, but when Jenny's boss turns up to enquire about her motives and dissuade her he seems so placidly accepting that you wonder why he bothered coming.
Even worse for The Unknown Girl is the fact that there's no levity to be found. Granted, Jenny's persona is one of dour professionalism throughout but no one else, not a patient, not a policeman has a sense of humour. In the whole film there's one funny moment when a kid with cancer sings Jenny a song. "I might as well examine you now I'm here," she says, obviously disturbed by this human-like behaviour. The resolution of the mystery is as implausible as any Agatha Christie novel and ultimately the film dips into a leaky melodrama. No doubt in a couple of years another Dardenne film will show up touted as their first experiment of another genre on the list. Let's hope it's something truly realistic, like a comedy, next time.
The 69th Cannes Film Festival takes place from 11-22 May 2016. Follow our coverage here.
John Bleasdale | @drjonty