Why France is still in love with Serge

To older Britons, Serge Gainsbourg will always be the ugly, unshaven Frenchman who sang a filthy pop duet with a sweet English rose.

To younger, rock-savvy Britons, Gainsbourg is the French singer and songwriter who managed to reverse, long after his death, the traditional flow of musical influence across the Channel or across the Atlantic. The French singer, who died in 1991, has inspired contemporary British and American bands such as Franz Ferdinand, REM and Portishead.

In France, he is remembered either as one of the great masters of chanson française or a drunken, pretentious, unpatriotic bore. Both sides of Serge Gainsbourg's career – and his little-known early years as a terrified Jewish child in wartime France – are explored in a bio-pic opening in France next week.

The movie, Gainsbourg, une vie héroique (Gainsbourg, A Heroic Life) is, in its way, as poignant and painful as the singer's own life. One of its principal roles, that of Gainsbourg's British muse and third wife, Jane Birkin, is played, brilliantly, by a young British actress, Lucy Gordon, who committed suicide soon after the film was completed last year.

The director, Joann Sfar, previously a writer of comic-strip books, has dedicated his movie to Ms Gordon, who was 29 when she died. "The film owes a great deal to the warmth, the sweetness and the immense talent of Lucy Gordon," Mr Sfar said. "Her personality was so luminous, so light, so funny."

French film critics who saw a gala première in Paris on Thursday night also gave high praise to Ms Gordon's portrayal of Jane Birkin. They were equally impressed by the performance of the French theatre actor, Eric Elmosnino, as Gainsbourg at the height of his career. They were less convinced by the model and actress Laetitia Casta's portrayal of the French sex symbol and queen of pout, Brigitte Bardot, one of the singer's many other conquests. A curiosity of the film is Mr Sfar's insistence that the actors must sing for themselves and not mime to original recordings. The recreation by Ms Gordon and Mr Elmosnino of the 1969 classic of heavy breathing and orgasmic noises, "Je t'aime, Moi non plus" – Gainsbourg's only global hit – is reasonably convincing. Other actors' efforts range from the effective to the courageous to the karaoke borderline. Mr Sfar admits that he has simplified and exaggerated the life of a man who, in any case, loved to caricature himself. By doing so he has angered Ms Birkin, now a 62-year-old English rose and the most popular Briton living in France. As the chief guardian of the temple of Gainsbourg's memory, she insisted that the film's title must be followed by a disclaimer describing it as not a biography but a "conte" or "folk-tale" by the director.

Another curiosity of the movie is the fact that Mr Sfar originally tried to cast the daughter of Serge Gainsbourg and Jane Birkin, the actress Charlotte Gainsbourg, as her father. Ms Gainsbourg considered this startling offer but then refused.

Mr Elmosnino, 45, looks, in fact, much more like the seductively unlovely Gainsbourg than the singer's beautiful daughter does. When asked once to explain his serial success with women despite what he described as his "cabbage-head" looks, Gainsbourg said: "Ugliness is superior to beauty because it lasts longer."

A further curiosity in the film is that Gainsbourg is portrayed as constantly battling with an alter-ego – humorous and creative but also self-destructive – which assumes a physical form, played by the American actor, Doug Jones. The director, Mr Sfar, said that he wanted to tell the story of a man who had a "love- hate relationship with his country and the women he loved ... a man who was terrified of being alone and had a desperate desire to be liked but muddled the love of his loved ones and the love of the public."

The story of Gainsbourg's often destructive relationships with women will also be examined in a documentary which will be shown on French TV next week.

Gainsbourg was born in Paris as Lucien Ginsburg, the son of a poor Russian-Jewish immigrant family in 1928. As a 12-year-old child in Vichy France, he was forced to wear a yellow star and was lucky to escape deportation to the death camps.

After the war, he attempted unsuccessfully to become a painter before finding work as a songwriter and a crooner in bars. Edith Piaf asked him to write songs for her but he declined.

His early career as a pop singer and pop writer, after his first album in 1958, was a mixture of rebellion, originality and cynical mimicry of commercial pop. He wrote songs for, among others, Juliette Greco, Petula Clarke and Françoise Hardy, Marianne Faithfull, Anna Karina and Nana Mouskouri.

He even composed a Eurovision Song Contest winner – "Poupée de Cire, Poupée de Son" – for France Gall in 1965.

He wrote an album of songs for the actress Catherine Deneuve and sang duets – and had a year-long love affair – with Brigitte Bardot. The infamous "Je t'aime. Moi non Plus" ("I love you. Me neither") was originally written for and recorded with Bardot but she banned its release (a judgement seconded by the BBC and the Vatican when the celebrated Jane Birkin version emerged in 1969).

In the last decade, Gainsbourg has become a cult hero and inspiration to British bands from Portishead to Franz Ferdinand. He has also been rediscovered by young people in his home country as one of the few truly original musicians that France produced in the classic years of pop and rock. He is now seen as a precursor of Queen or David Bowie – as someone who successfully spliced rock and jazz and classical music and a writer who produced poetic rather than crass pop lyrics (although he also wrote plenty of those in his time).

The first half of the 130-minute movie follows Gainsbourg's life when he was still Ginsburg, a shy, poetic boy and teenager, ashamed of what he calls his "ugly Jewish face". The second half – less effective according to French critics – shows his emergence as "Gainsbourg", the provocative womaniser and singer-songwriter. It ends with his descent into alcoholism as the man that the French press nicknamed "Gainsbarre".

But the film steers clear of one of his most disturbing aspects: his obsession in song with the sexual attraction of under-age girls.