Martin Margiela, the "Greta Garbo of fashion," is lurking somewhere out of sight at the Palais Galliera in Paris where a huge retrospective of his work opened Friday.The reclusive genius - of whom no photograph exists after 1996 - walked away from his label nine years ago when he was the most talked-about designer in the world, and has not been seen in public since.Two new Paris exhibitions lift a little of the mystery that surrounds Margiela, arguably the most influential designer of the last 30 years.Forever the control freak, he has quietly guided both from behind the scenes, taking top billing as "artistic director" from curator Alexandre Samson for the Galliera show.It is a small sacrifice given the impact the enigmatic creator, still only 60, made before disappearing into thin air.

The Belgian blew away the sexed-up, money-obsessed extravagance of 1980s fashion by scandalously recutting secondhand clothes for the catwalk.

He turned a butcher's apron into an evening gown, black leather gloves into a breathtaking corset dress and made a now iconic blouse from several pairs of white socks in his first Paris shows.

While the big luxury brands were outdoing each other in the decadence of their shows, Margiela staged his in an abandoned metro station, a Salvation Army hall, and most notoriously in 1989 on a piece of waste ground in one of Paris' roughest neighborhoods.

Laughing local children pushed in beside critics in the front row and ran after his models down the bumpy "runway," with some being lifted onto their shoulders.

Raf Simons, the former Dior designer now leading Ralph Lauren, said that Margiela changed fashion forever that night in 17 joyous and shambolic minutes.

The "bleak fairyland" Margiela had created was "so angelic and alien," Simons said, that "I started to cry".

"I thought, ‘How stupid to be crying at a fashion show.' Then I looked around, and half the audience was crying."

This was a full-on rebellion against the "star system of the time which he really disliked," said Samson.

The 1980s body beautiful aesthetic also went out of the window. Instead, Margiela cast his friends -- the more odd and original the better -- in his shows.

In the age of the supermodel, he covered his models' faces to better see the clothes, and designed with an eye also for "women of a certain age."

"He turned his back on the ways things were supposed to be done," Samson told AFP.And in the case of the clothes Margiela made from coat and dress linings, he literally turned fashion inside out.

But his biggest transgression was thumbing his nose at designer labels.

His own was simply a numbered square of white cotton.

Margiela began his rise as an assistant to the extrovert French creator Jean Paul Gaultier. He told the documentary, "The Artist is Absent," that Margiela was the best he ever had. "I was not his teacher," he said, "because he didn't need one."

As far back as 2000, when the trend was for skin-tight, Margiela had invented oversized, which nearly two decades later is still one of fashion's most dominant looks.

His duvet coats, long striped blue shirts, Japanese-style Tabi shoes and thigh-high stiletto stocking boots have all been "referenced" by fashion's wunderkind of the moment Demna Gvasalia, whose collections for Vetements and Balenciaga often seem like Margiela tribute shows.

Samson said he "loved playing with scale," blowing Barbie and Ken doll clothes up to human size.Margiela's then PR Patrick Scanlon argued that "his incredible apprenticeship" with Gaultier taught him to see "anonymity as an advantage."

"There was no need to feed the media beast, it was a double-edged sword."

While the second Margiela show at the Museum of Decorative Arts, which opens on March 22, will concentrate on his five years at the luxury brand Hermes, the Galliera exhibition uses over 1,000 objects from his archives to illustrate his 20-year career.

Neither show, however, solves the mystery of why Margiela left the stage so suddenly in 2009 when he was at the height of his powers, wowing his fans with a coat made of wigs in his startling final show.

Simons believes he "had said what he wanted to say. Basta! I find that admirable. That's what more people should do," he added.