Philippe Chancel was only 20 years old when he first encountered the Vikings, a street gang whose teenage members hung out on the streets of central Paris in the early 1980s. He was immediately struck by their retro style, based on 50s rock’n’roll: check shirts, pleated trousers and sculpted quiffs for the boys; gingham tops, hooped earrings and polka-dot headscarves for the girls.

Chancel was further intrigued by the fact that, while most gang members in Paris at the time were white, working-class youths who espoused ultra-rightwing views and racist attitudes, the Vikings came from a variety of ethnic backgrounds.

“Back then, the Vikings were the exception because they were black, blanc, beur,” says Chancel, employing a well known term to describe France’s multi-ethnic culture (“beur” meaning French of North African origin). “That made me curious. I wanted to shoot them from the inside over a period of time. I think they accepted me because I was also young and had confidence and attitude. I wanted to find my place in life so I was looking for thrills and ready to face extreme situations, taste the real life. Photography was a good pretext.”

Chancel’s photographs of the Vikings and of another, allied gang, the Panthers, were published in the French counterculture magazine Actuel in the 80s but have remained relatively unseen since. Now they will be included in a forthcoming exhibition, Another Kind of Life: Photography on the Margins, which opens at the Barbican, London later this month. It looks at outsiders – “sexual experimenters, romantic rebels, outlaws, survivalists, the economically dispossessed and those who openly flout social convention” – through the lens of photographers including Jim Goldberg, Larry Clark, Mary Ellen Mark and Pieter Hugo.

Chancel photographed the Vikings and the Panthers throughout 1982. The majority of his black-and-white images capture a relatively innocent time, when dancing, clubbing and hanging out were the main concerns of these rebellious teenagers. “The spirit of the times is one of tribes, of style,” Chancel noted back then, identifying a pivotal pop culture moment when the dress codes of the recent past were being reappropriated in the style-conscious early 80s.

Facebook Twitter Pinterest ‘Even if you got to know them, some of these guys could be very unpredictable,’ says Chancel. Photograph: Philippe Chancel

It was a time, though, when French politics was becoming polarised as the beleaguered leftwing government struggled to survive against a backdrop of rising unemployment. It was in 1983’s municipal elections that the Front National first became a presence in French politics when its leader, Jean-Marie Le Pen, won a council seat in the 20th arrondissement. As immigrants were being increasingly scapegoated for the country’s troubles, the Vikings and, in particular, the Panthers became both more organised and more aggressively anti-racist.

The Vikings had named themselves after the first successful multiracial rock’n’roll group in the 1950s, the Del Vikings, while the Panthers honoured the American revolutionary movement the Black Panthers. Made up of young, second-generation West Indians, the Panthers borrowed their look – vintage air-force jackets and caps – from black GIs and many of them practised martial arts. In their use of often violent direct action, they were at the vanguard of a network of leftwing Parisian street gangs that, as the decade progressed, came to be known collectively as antifa (anti-fascists) and chasseurs de skins (skinhead hunters).

One of the most striking aspects of Chancel’s series is the way the tone suddenly shifts from the celebratory to the ominous. While accompanying the gang members on their nocturnal forays into central Paris, he photographed a youth brandishing a wooden club, baseball bats being concealed in a kit bag, and a shotgun lying in the boot of a car. “I was friendly with them, but an enemy, too,” says Chancel. “It was difficult to manage my position and I had to learn fast the language of diplomacy. As things developed, it became more risky. Plus, I was using flash and that is not the most discreet way to photograph. Sometimes the reaction could be very aggressive.”

The Vikings alone had around 100 members in the early 80s and both gangs controlled a territory that spread from the north-eastern suburbs to Gare de l’Est. Skirmishes with rival gangs sporadically broke out in bars and music venues across the city and there were several running battles amid the crowds at the popular flea market at Clignancourt. “I was on alert for a lot of the time,” recalls Chancel, who went on to become a well known photojournalist, covering conflict in Kabul and everyday life in North Korea. “Even if you got to know them, some of these guys could be very unpredictable. There were situations when they did not like me to be there with my camera.”

Was he shocked to realise some of the gang members had guns?

“Yes, for sure, but I thought at first it was just showing off, or maybe also for their protection. It is even more shocking now because all of this was happening, not just in the banlieues (suburbs), but on the major boulevards of Paris. In the context of today’s high levels of security, it seems unbelievable, almost impossible.”

In early 1983, for reasons that have been lost to the passing years, the Vikings and the Panthers clashed violently on the streets of Montmartre, signalling the abrupt end of their alliance. By then, Chancel had already moved on. He tells me that many of the young people in his photographs are now dead “from accidents to do with drugs, excess, the violent lives they lived”. His wonderful images evoke a brief time of innocence before the fall. “The past is the past,” he says now, wistfully, “but looking at my photographs now, they seem like a record, not just of another time, but another world.”

Another Kind of Life: Photography on the Margins is at the Barbican, London from 28 Feb to 27 May