Don't ask me why, but it's much easier to tolerate monotony in a foreign-language film. Of course, this is not what any writer/director wants to hear, least of all The Past's Asghar Farhadi, who won an Oscar for A Separation in 2011. But this back-handed compliment is my way of saying that it is possible to watch, and even enjoy, an interminable (over two hours) study of a dysfunctional family living in a drab Parisian suburb in a way that I would struggle to do if it was set in, say, Peterborough.

Not that good relationship movies don't get made in Cambridgeshire (give me time and I'll think of one), but the intensity and mood of a kitchen sink drama in French is that much moodier and more compelling. For the Iranian filmmaker, the theme of break-ups and family discord is also safe terrain as he has seen artists from his homeland who strayed into political or religious commentary do so at their peril.

Rather than take that risk, Farhadi has written the story of Ahmad (Ali Mosaffa) who after four years of separation, has come from Iran to France to finalise his divorce from Marie, a complicated woman with an equally complicated love life.

There are also two daughters from a previous relationship, one of whom, Lucie (Pauline Burlet), is desperately unhappy. Casting The Artist's exquisite Bérénice Bejo as emotional Marie was an inspired choice, for she is even more beautiful in colour than in black and white - and with dialogue can really deliver.

The plot thickens, albeit under simmer slowly instructions, when the patient Ahmad discovers that Marie's new boyfriend (Tahar Rahim) with whom she is expecting a child, also had a wife in a coma who allegedly committed suicide. Could this be the root of Lucie's hostility? As Ahmad turns detective/samaritan, we become embroiled in guilt, suspicion, betrayal and lots of shouting, much like an epic episode of EastEnders. But when you're in Paris it's art.

There is guilt, suspicion and lots of shouting