Pure evil is all around in this unnervingly subtle, sophisticated movie; it is a conspiracy drama-thriller, shot with a kind of desiccated blankness, about the occult world of super-wealth and things not to be talked about. The title is a Swiss banker’s codeword in conversation for “be silent”. It is set in 1980 in Argentina, at the time of the junta’s dirty war against leftists and dissidents. Azor gives a queasy new perspective on the horror of those times, and there is even a nauseous echo of the Swiss banks’ attitude to their German neighbours in the second world war.

Yvan (Fabrizio Rongione) is a private banker from Geneva – elegant, discreet, an excellent speaker of Spanish, English and French – who is making what appears to be an emergency diplomatic visit to soothe his well-heeled and secretive clients in Argentina, in the company of his elegant, supportive wife Inès (Stéphanie Cléau). Yvan’s rich clientele are deeply troubled by the new political regime; they fear that they could find their assets being sequestrated by the government. And what is even worse is that these people were used to dealing with Yvan’s colleague Réné, a genial and exuberant figure who has also now vanished.

Part of the chill in Azor is the professional calm cultivated by Yvan and Inés; Yvan affects never to be really upset or distressed about what has happened to Réné and what is happening all around him. There is something dreamlike in the series of social calls that Yvan and Inés make to a succession of wealthy, elderly, melancholy people who sense that their lives and their prosperity are coming to an end but never respond to any sense of emergency. It is a film that continues to echo mysteriously inside my head.