“Cocteau seems to have observed one single external and internal command: ‘be modern’,” writes Dominique Paini, chief curator of the biggest ever exhibition devoted to Cocteau’s life and work, entitled Jean Cocteau: Sur le Fils du Siècle (Jean Cocteau: Spanning the Century), which recently opened to record-breaking crowds at the Pompidou Centre in Paris.

Dream-like and labyrinthine under crepuscular lighting, the exhibition is a bravura reclamation of an artist once deemed a “touche à tout” (a dabbler) and who wrote in 1926, perhaps describing the ambiguities of his own reputation: “The worst tragedy for a poet is to be admired through being misunderstood.”

Only now, it would seem, are we beginning to comprehend the sheer scale of Cocteau’s significance — his lifelong devotion to modernity, and to the broadest potential of art and aesthetics, which now makes him appear so contemporary. He was an artist who worked across a range of media — diluting his genius, perhaps, but blurring all boundaries of cultural or aesthetic status.

The exhibition features 335 drawings, 300 photographs, 22 paintings by major artists who celebrated him, 50 or so manuscripts, objects and sculptures. A projection room shows an anthology of his films: Le Sang d’un Poète, Orphée, Le Testament d’Orphée, Les Enfants Terribles, La Belle et la Bête, Les Parents Terribles.

Whether working in poetry, film-making, magazine publishing, ceramics, erotica, fashion, interior design or avant-garde musical theatre, Cocteau was more than simply the results of his creativity. Throughout his career — which neatly spans the trajectory of European Modernism from around 1905 to his death in 1963 — he existed as a force within the culture: as an agitator and an instigator, a one-man phenomenon weaving a mythology around himself in which he seems to become his own greatest creation.

Small wonder that Andy Warhol, a fellow traveller down the road to self-enshrinement, made no fewer than three portraits of Cocteau. Newsreel footage from the 1950s — snappily titled La Vie Artistique — shows Cocteau the public figure and French institution: a slender-looking man with bird-like features, strangely regal in his dinner suit and waist-length cape, arriving at some prestigious Parisian function. But how extraordinary was Cocteau’s life?

From the very beginning he seems to be living to the script of some febrile and intoxicating drama — inhabiting the often perilous passage between daily reality and an inner, magical world which is best described as the consciousness of poetry. He was born in 1889, to a wealthy Parisian family living at Maisons-Lafitte, just outside Paris. His father was a lawyer and an amateur painter who killed himself when Cocteau was just nine — a tragedy which has led some psychoanalytical critics to suggest that such violent evidence of human frailty prompted him at an early age to dedicate himself to the compensations of art, which he later called “a religion without hope”. The imagery of woundings and stigmata would be crucial in Cocteau’s art — never more so than in his film Le Sang d’un Poète, made in 1930.

With his father’s suicide, Cocteau seems to abandon the enchanted world of his childhood — where to all intents he was blissfully happy — and start to seek reinvention as an artist. When he was 16, he ran away to Marseilles, becoming “liberated”, according to his own testimony, by spending time in the most dangerous quarters of the city.

Filmic and mythic, such a rite of passage would correspond with his subsequent lasting friendship with Jean Genet — the writer, petty criminal and dramatist who shared not only Cocteau’s homosexuality, but, more important, his fascination with the proximity of daily life to the magical, inner world of fantasy.

Sensuous early portraits of Cocteau by Jacques-Emile Blanche show an elegant, extravagantly handsome young man who looks every bit the dandified aesthete. Similarly, photographs of the young Cocteau taken when he was wintering at Cap Ferrat with his first great love, the writer Raymond Radiguet, show a bronzed, sinewy man with a shock of dark hair. By 1915, Cocteau had already met and been befriended by Proust and Picasso, and in 1917 — challenged by the Russian ballet-master Sergei Diaghilev to “astonish me!” — he wrote the great ballet Parade. With music by Erik Satie and sets by Picasso, Parade remains one of the principal statements of European Modernism, a work that confounds both Surrealism and Dada, and creates its own high aesthetic, part circus fantasy, part futurist pageant.

Cocteau’s 1920s were filled with glamour and ended in neurasthenia: Kiki de Montparnasse, Gertrude Stein and François de Gouy d’Arcy were all in his circle in the South of France, where he conceived a “danced operetta” to celebrate the Riviera “train de luxe” The Blue Train, and wrote of drunken sailors belly-dancing with whores.

The premature death of Radiguet from typhoid fever, however, led Cocteau to an addiction to opium. It also marked the point at which Cocteau’s work becomes fixated on the ability to see clearly into the world of the dead — as would later be evidenced by his collaboration with Stravinsky on Oedipus Rex and his original one-act tragedy Orphée. When Coco Chanel paid for his rehabilitation, Cocteau wrote about his addiction in Opium, published in 1930.