‘When he said he was in Toulouse for paediatric training, he was in Krakow seeing his other wife.” This is the moment when a Parisian woman called Marianne discovered that her partner had a second life. And a third, and a fourth … The Man With a Thousand Faces slots neatly into the mini-genre of dating scammer documentaries – but this is the French-intellectual version. There are some jaw-droppers in the story of how Ricardo (sometimes Alexandre or Daniel), a Portuguese (sometimes Argentinian or Brazilian) man conned numerous women. But it’s an emotionally literate, lo-thrills film from film-maker Sonia Kronlund, who casts actors to play some of the women to protect their privacy.

And really, it’s the women that Kronlund finds compelling. Marianne (played by Aurelie Gasche) had a baby with Ricardo, supposedly a surgeon who’d spent years in Africa with Médecins Sans Frontières. She was five months pregnant when suddenly she couldn’t reach him; the phone numbers he’d given her were fake. Another woman discovered the truth after finding a photo that he’d sent to the mother of his baby daughter – only they didn’t have a baby. Ricardo’s typical exit strategy at the end of a relationship was to vanish after getting a phone call to say that one of his parents was dead or in a coma.

Director Sonia Kronlund hires a detective to find Ricardo, who is married and living in Krakow. Her revenge will feel like an anticlimax for anyone gearing up for a showdown. But Kronlund understands men like Ricardo; she gets that he is untroubled by shame. It would be impossible to make him feel guilty about how his lies have devastated his former partners. So instead she makes him look silly, showing him up as a needy narcissist desperate for attention. It’s a masterstroke, although her film leaves a fair few questions unanswered.

• The Man with a Thousand Faces is in UK cinemas from 22 November.