Coco Before Chanel, Anne Fontaine, 110 mins, (12A)<br></br>Crossing Over, Wayne Kramer, 113 mins, (18)

This flimsy story of Coco Chanel's early years just leaves you wondering what happened next

The prevailing blockbuster template of the past decade has been the prequel – the film-length flashback which explains how Bruce Wayne took to crime-fighting in fancy dress (Batman Begins), how James Bond got his double-0 (Casino Royale), and how Kirk got himself promoted over the better qualified Spock (Star Trek).

Gabrielle "Coco" Chanel might have been a fashion designer rather than a superhero (although some devotees would put her in both camps), but otherwise this burgeoning sub-genre fits Coco Before Chanel like an over-priced glove. An account of her pre-fame years, it has the customary Freudian glance back at her childhood, the customary shots of her developing her best-known skills and predilections, and the customary intimations of what's in store for her later on. It also leaves the viewer with the customary suspicion that the juicy stuff is all going to happen after the end credits have rolled.

After a prologue that sees the young Gabrielle being dumped at an orphanage's front door by her father, we meet her again as an adult (Audrey Tautou), seamstressing by day, and duetting with her sister in a provincial cabaret by night. The sisters' signature ditty is about a dog called Coco, which is apparently reason enough for a roué in the audience to declare that that should be Gabrielle's nickname – and reason enough for Gabrielle to go along with the notion, rather than emptying her drink all over his trousers.

It's lucky she's so obliging, because the roué turns out to be an aristocratic landowner, Etienne Balsan (Benoît Poelvoorde). Still hoping to make it as a singer or an actress, Coco invites herself to Balsan's country estate, where he provides her with bed and board, on the understanding that it's his bed she sleeps in. Conveniently, every single one of the high-society women she meets at Balsan's decadent parties is trussed up in a dress that's a mass of bows, brooches, flowers and feathers, so Coco is soon telling everyone who'll listen that they should be wearing simpler, more androgynous clothes.

It's all as reductive as that. We're shown repeatedly that corsets are sweaty and uncomfortable, so Coco doesn't approve of them. Coco can't afford fancy dresses, so she opts for plain ones. Coco wore black when she was in her orphanage, so that's what she thinks everyone should wear. Maybe the process of revolutionising 20th-century fashion really was as prosaic as that, but you start to wonder what all the fuss is about.

A love triangle forms when Balsan introduces Coco to his friend, Arthur "Boy" Capel (Alessandro Nivola). When he's not sitting moodily alone in the drawing room playing the piano, this tall, dark and handsome English industrialist encourages Coco to set up shop as a milliner in Paris. The pair of them fall for each other, but there are enough obstacles in the path of their relationship to turn Coco Before Chanel into a Mills & Boon-worthy tragic romance. It rolls along smoothly and tastefully, with as many carriages and country houses as any Jane Austen adaptation (although, ironically, the elaborate frocks we're invited to admire in any other period drama are the ones that we're meant to sneer at here). But considering its subject matter, there's precious little flair, and it relies on Tautou for much of its depth and intensity. Banishing all memories of Amélie, she's a coiled spring of resentment who becomes steadily more regal and authoritative as she finds her calling.

Tautou's performance aside, Coco Before Chanel isn't very engrossing if you're not already an acolyte, and it isn't very revelatory if you are. Certainly, none of the story we get compares with what we don't get: her subsequent success, her affair with Stravinsky, and her wartime liaison with a Nazi spy. In its focus and its style, Coco Before Chanel is like the first part of a TV mini-series, so we can only hope that Coco During Chanel and Coco After Chanel are still to come.

Another film that's not quite as profound as it wants to be is Crossing Over. It appears to be the work of a writer-director who watched Crash and reasoned that the way to win an Oscar was by making a sprawling issue-drama set in Los Angeles. The issue he's gone for is illegal immigration. Harrison Ford heads the cast as a customs enforcement cop who's going soft in his old age. Ray Liotta, Ashley Judd, Jim Sturgess and a largely naked Alice Eve are among the other people who are either trying to kick someone out of the country, or avoid being kicked out themselves.

Judging by the number of recent American films which have been concerned by illegal immigration, it's taking over from Iraq as the topic of choice for politically inclined Hollywood directors. But, unlike last month's Frozen River, Crossing Over doesn't bother to embed the topic in a compelling story. Instead, the characters are always having to pour out unwieldy monologues about the evils of restricted immigration. The most egregious example is a scene in which a policeman pontificates about "the sublime promise" of US citizenship to a convenience-store robber who's holding a woman at gunpoint. You'd think that all three people in the scene might have had more pressing matters on their minds.

Also Showing: 02/08/2009

Rumba (77 mins, PG)

This Belgian, almost-silent comedy is a compilation of cartoonish sight gags. They're strung together into the story of two frighteningly skinny primary school teachers who spend all their free time at Latin dance contests until a car accident robs the husband of his memory, and the wife of half her leg. Jacques Tati fans should seek it out, but it's funny in theory more often than in practice. As brief as it is, the meticulous whimsy and sickly 1970s colour scheme, grow tiresome well before the end.

Mad, Sad & Bad (98 mins, 15)

Brit-Indian ensemble comedy drama about three grown-up siblings (Meera Syal, Nitin Ganatra and Zubin Varla), struggling to sort out their love lives, and to break away from their dipsomaniac mother. It deserves credit for sidestepping as many clichés as it does: it must be the first Anglo-Asian film in which mixed-race relationships pass without comment. But despite some decent lines, and fine performances from the three stars, it's a flatly shot, sluggishly paced effort that promises better work from the writer-director in future – especially if he learns that having someone list different varieties of cheese isn't always hilarious.