Frédéric Tcheng's fly-on-the-wall documentary follows the fortunes of Christian Dior, from the arrival of the new artistic director to the seamstresses and pattern cutters.

For some people, fashion reigns supreme. As Christian Dior himself said: "Finally, everything that has been part of my life, whether I wanted it to or not, has expressed itself in my dresses."

Christian Dior's new artistic director Raf Simons has his work cut out for him as he prepares for his first haute couture collection. Even for those not remotely interested in fashion, this film explores the universal themes of obsession, glamour and money.

It is a rare glimpse into the lives of the real heroines – the seamstresses – some of whom have spent over 40 years stitching, sewing and cutting fabrics to create some of the most expensive and coveted frocks on the planet.

In the first few intense scenes, we are brought into the Paris fashion house as Simons is introduced to the Dior staff. The former Jil Sander creative director is understandably nervous, licking his dry lips and looking shyly about him.

When asked if he would like to be called "Monsieur" or "Raf", he replies that latter, in a nod to modernity and less formality. He seems an approachable, humble chap. But looks deceive and as soon as the Belgian atelier doesn't get his dresses delivered on time, he has a hissy fit. "You do not say no to me," he warns.

The film is intercut with ghostly black and white images of Christian Dior and a voiceover with passages read out from his autobiography. It does give the feeling that the great man is watching over the proceedings, never totally letting go of the reins.

The men may hold the positions of power in the fashion house, but it is the women who hold the keys to the success or failure of the brand. In particular, premieres Florence Chehet and Monique Bailly. Under time pressures and the difficulties of creating complicated patterns, the women turn to their secret weapon – snacking on Haribos.

A rare look behind the scenes in the fashion world where money and big business vies with creativity for supremacy.

Dior and I opens in London on 27 March 2015