What do Norman Mailer, Saul Bellow, Ellsworth Kelly, Simone de Beauvoir, Alberto Giacometti, Albert Camus, Jean-Paul Sartre, Juliette Gréco, Miles Davis, Boris Vian, Alexander Calder, Samuel Beckett, James Baldwin, Janet Flanner, Arthur Koestler, Richard Wright and Irwin Shaw, to name but a few, have in common? They were young, together, in Paris.

More like this:

- The man who created Paris

- The photo that symbolises Paris was faked

- Were Sartre and Beauvoir the first modern couple?

Left Bank is a portrait of the overlapping generations born between 1905 and 1930, who lived, loved, fought, played and flourished in Paris between 1940 and 1950 and whose intellectual and artistic output still influences how we think, live, and even dress today. After the horrors of war that shaped and informed them, Paris was the place where the world’s most original voices of the time tried to find an independent and original alternative to the capitalist and Communist models for life, arts, and politics - a ‘Third Way’.

Those young men and women, budding novelists, philosophers, painters, photographers, poets, editors, publishers and playwrights, shaped by the ordeals of World War Two, did not always share the same political or cultural outlook, but they had three things in common: the experience of war, their brush with death and the elation of the Liberation of Paris. And they promised themselves to reenchant a world left in ruins. I wanted to tell the story of their life­-changing synergy and explore the fertile fields of interaction among art, literature, theatre, anthropology, philosophy, politics and cinema in post-war Paris.

When editorialists and artists shouted on the Boulevard Saint­ Germain, their cry echoed in Manhattan, Algiers, Moscow, Hanoi, and Prague

After four years of Nazi occupation and daily torment, Paris’s galleries, boulevards, jazz clubs, bistros, bookshops and the myriad daily news­papers and monthly reviews born in the last years of the war became forums for heated discussions, battle plans and manifestos. Among the most influential periodicals: Combat, edited by Albert Camus; Jean-Paul Sartre and Simone de Beauvoir’s Les Temps modernes (named after Chaplin’s film Modern Times); and of course, a few years later, the many Paris-­based English-­language magazines catering to an international crowd of ex-­GIs and students flocking to the city. These flourishing publications, all edited within one square mile, boasted an audience well beyond Paris. When editorialists and artists shouted on the Boulevard Saint­ Germain, their cry echoed in Manhattan, Algiers, Moscow, Hanoi and Prague. These intellectuals, artists, and writers were heard and followed by decision makers in Europe and elsewhere in the world precisely because they originated from Paris.

Together, in Paris, this band of brothers and sisters created new codes. They founded the New Journalism, which got its official name a decade later but was born then, in the smoky hotel rooms of the Left Bank, and forever blurred the lines between literature and reportage. Poets and playwrights slowly buried Surrealism and invented the Theatre of the Absurd; budding painters transcended Socialist Realism, pushed Geometric Abstraction to its limits, and fostered Action Painting. Philosophers founded new schools of thought such as Existentialism while setting up political parties. Aspiring writers found their voices in Paris’s gutters and the decrepit student rooms of Saint ­Germain ­des ­Prés, while others invented the nouveau roman.

Photographers reclaimed their authorship through photojournalism agencies such as Magnum; censored American writers such as Henry Miller published their work first in French; black jazz musicians, fleeing segregation at home, found consecration in the concert halls and jazz clubs of Paris, where New Orleans jazz received its long ­overdue appreciation while bebop was bubbling up. Some in the Catholic Church experimented with Marxism, while a colourist and former art gallery owner-turned-couturier named Christian Dior intoxicated the world with the ‘New Look’ in fashion design.

After 1944, everything was political; there was no escape

After 1944, everything was political; there was no escape. World citizens of the Left Bank knew this, and they did all they could to question both US policies and the Communist Party’s views. Paris was, for them, both a refuge and a bridge to think in a different way. They opened up the possibility of a Third Way, ardently embracing the idealism of the United Nations and the glimmer of utopia in what would later become the European Union.

Those pioneers also reinvented their relationships to others. They questioned, shook, and often rejected the institutions of marriage and family and adopted polyamory as an ambition in life. They campaigned for the right to abortion 30 years before it was legalised and consumed drugs, cigarettes, and alcohol with passion. Their heightened sexuality proved an inherent part of their creativity and permeated everything they did. They also proved, with only a few exceptions, to be very hard workers, workaholics even. They worked hard and played hard.

A ‘third sex’?

Women took on a central role. The Mona Lisa’s return to the Louvre after six years of hiding during the war heralded a new era in which Elle magazine was founded and edited by 29-year-old Françoise Giroud, who would become a government minister exactly 29 years later. As Colette, the grande dame of French literature, passed away, so did the figure of the demi-mondaine. Bardot and Beauvoir became the two new faces of feminism to whom the world would soon surrender. In this predominantly male environment, only very strong women survived and made a mark. You had to be pugnacious in those years if you wanted to exist as an individual and not just as the escort of a great man.

Women who refused to be just wives, or mistresses, more often than not exploited by their famous and unfaithful other halves, were almost all bisexual, and female Don Juans. Some were even on the quest for a Third Way into sex, as in politics. The New Yorker’s Paris correspondent Janet Flanner, who signed all her articles with the pseudonym Genêt, known before the war for her statuesque and beautiful female lovers, asked her liberal mother in a letter in 1948: “Why cannot there be a third sex, a sex not dominated by muscle or the inclination to breed?” A good question in a decade bursting with testosterone.

All of them - male and female, artists and thinkers - set new codes and standards, achieved a string of undeniable successes, and left behind a litany of failures. Tony Judt addresses the latter in the academic work Past Imperfect: French Intellectuals 1944–1956. His resentment and frustration pour from the pages like those of a spurned lover. Paris intellectuals had so much power bestowed on them by circumstances and their own genius and yet failed, in his view, to change the world. “This contrast, the failure of French intellectuals to fulfil the hopes invested in them by their admirers, together with the influence exerted by the French intellectual life in other Western countries, had a decisive impact on the history of post-war European life.” Tony Judt, himself shaped by French thinking, would never forgive Sartre and co for having let their contemporaries down when they needed them most. He even called his book “an essay on intellectual irresponsibility.” That they were expected to change the world in the first place raises the question: how did they arouse so much wild hope? Left Bank is as much about post-war Parisian intellectual irresponsibility as about political, artistic, moral and sexual incandescence.

Left Bank, Arts, Passion and The Rebirth of Paris 1940-1950 is released in the US by Henry Holt, and in the UK by Bloomsbury.

If you would like to comment on this story or anything else you have seen on BBC Culture, head over to our Facebook page or message us on Twitter.

And if you liked this story, sign up for the weekly bbc.com features newsletter, called “If You Only Read 6 Things This Week”. A handpicked selection of stories from BBC Future, Culture, Capital and Travel, delivered to your inbox every Friday.