"Ah, la Piaf est morte. Je peux mourir aussi."

Piaf is dead. I can die too… These are said to be the last words of Jean Cocteau, who on hearing the news Edith Piaf had succumbed to liver cancer at 47 then allowed himself to pass away on the spot, an exquisitely-timed heart attack the final act, and the pair were no more within hours of each other. If Cocteau had little time to mourn the loss of France's greatest chanteuse, then the whole of Paris could reflect and lament at leisure at the passing of its most famous daughter. The people apparently mourned in their droves.

La Môme Piaf is more than just a singer, she's emblematic of struggle and of triumph over adversity. She is as French as mistral typeface superimposed over a chugging Citroën DS shot in grainy black and white with a handheld camera. She is regarded as an implacable icon, and international success in her own lifetime endeared her unconditionally to her loyal masses back home. A famously tiny woman, she was a towering and ubiquitous figure at a time when ubiquity was only bestowed on the very special.

In many ways you could say she represents the beating heart of the working classes situated in the faubourgs of the great city - or at least she once did, before the working classes moved out to the ever-expanding suburbs. That's not to say she only appealed to the proletariat: the barkeepers and bistro owners and the paras of the Foreign Legion who marched defiantly to 'Je Ne Regrette Rien' as top ranking officers failed in their coup d'etat to overthrow President de Gaulle in 1961. Her appeal was vast when she was alive, it transcended politics and fashion, it soared above the mansard roofs and out beyond Paris's périphérique, enveloping the rich and the poor and everyone in the middle.

Whether this adoration absolu is still in place in the 21st Century is debatable. To say Piaf now has cross-generational appeal is pushing it, though there are more than a handful of singers willing to stand up in patriotic solidarity and some who even profess love (more on them later)... but what of the young? It might be fair to say, as an observer of Anglo Saxon origin and a ville lumiere interloper, that her spectre appears to preside over Paris benignly now. You see Gainsbourg graffiti on the streets and his face on film posters and poking out of shop windows, but the same can not be said of Edith. She's certainly part of the tapestry in the same way La Belle Époque is, though while that is remembered fondly by people whom we can safely say weren't actually there, those fond of Piaf seem to be the people who were there. Could it be her legacy is not as assured as one might have assumed? To say so in France is unthinkable, blasphemy even, and yet the idea she will endure could be more a received wisdom than one based on any current appropriation by younger generations and the generations that will follow.

I became aware there'd be celebrations to mark 50 years since the singer's death on the day I visited the Musée Édith Piaf in late August 2013. It's an unusual private museum, tucked away in an apartment block in a quiet street off the more rambunctious Rue Oberkampf. Open since 1977, it has existed in these two rooms under the curatorship of Bernard Marchois, biographer and close confidante to the Famille Gassion-Piaf. Viewing has to be done by appointment only and once booked with Bernard via telephone (he has no secretary) one is given a door code and instructions that lead you through a gate and then up to the apartment via an escalator. As we're ushered in, a group of enthusiastic, sexagenarian American men who could just as easily be fans of Liberace leave.

Once inside, Bernard first alerts us to a life size cutout of Piaf, and at 4 ft 7 you are struck by just how small she was. Then you become aware of a dusty old pair of boxing gloves in a perspex box, the belongings of the late heavyweight champion Marcel Cerdan, her star crossed-lover. He was en route to surprise her in New York when the Lockheed Consellation that he was travelling on plummeted into the Alps; his spur of the moment decision to visit her packed an even bigger punch than the one intended. A little black dress she wore while performing in the Big Apple (she fastidiously - and some would say superstitiously - always wore black with red lipstick) is the other curio worth a look in, then it's all paintings and more paintings and letters to friends - including Marlene Dietrich - and you wonder how all this miscellania fits into these two small rooms.

Meanwhile Bernard sits at a desk, humming along to Edith 78s played on an old gramophone. I disturb him with the request of an interview, though he informs me he'll be taking a break from the museum to go on vacation right up to the quinquagenary. He presents me with a sheet of events and then highlights in a fluorescent pen the prefered engagements, including a commemoration at l'église Saint-Jean-Baptiste de Belleville where she was baptised and a blessing at her final resting place. Piaf was buried at Père Lachaise cemetery in east Paris in October 1963. With a magnificent view down onto the city, she rests on the slope of a hill near the great and the good alongside her stuffed rabbit, lion and squirrel. She's a stone's throw away from Oscar Wilde and not far from the Mur des Fédérés, the site where 147 communards were executed and thrown straight into a pit in 1871. Frédéric Chopin, Marcel Proust, Sarah Bernhardt and Jim Morrison are just a few of the legends left hanging out there for all eternity.

October 10th is the big day, says Bernard, though there are celebrations spread from Thursday through until Sunday in Belleville, where she was born in December 1915. No stranger to her own mythology, she claimed to have been delivered on the steps of 72 Rue de Belleville. A plaque there on the wall reiterates this and adds quite rightly that she was born into great poverty, though records show she was actually registered at the nearby Tenon Hospital on Rue de la Chine. She did live in a bordello for a while, though that was in Normandy, when she stayed with her mother before she was plucked away by her father, a circus performer who encouraged her to sing for her supper. While at la maison de prostitution she was blinded by keratitis, a kind of herpes, and it was on a pilgrimage to Saint Thérèse of Lisieux where her sight was allegedly restored. Knowing what we know now, the "healing" might have had more to do with her being removed from a house of hookers with STDs aplenty than any petitions to the Almighty, but this incident ensured Piaf would remain a staunch Catholic her whole life, or at least a staunch Catholic with strong influences of spiritualism and - as is the case with many a left-footer - more than a soupçon of superstitiousness to guide her.

It's the Catholic church where we first encounter Piaf's fanbase. Saint John-Baptiste de Belleville is a large neo-Gothic structure completed in the mid-19th Century, and it is probably fuller on the occasion of this mass to commemorate her death than it has been in decades. TV cameras are present, there's a full compliment of priests and Bernard is holding court near the front ahead of the service. A contingency of Belleville's large Chinese and Vietnamese population are present to pay their respects, then it's white hair and dotage as far as the eye can see. To presumably be one of the youngest people in a building full of hundreds is a rare experience indeed for me these days.

Later that evening the road is closed and a marquee is set up outside the church where singers perform the songs of Piaf to a depressingly select and dwindling audience. The blue lights from the gazebo are overpowering; a man and his dog stood in isolation to the left of me appear as though they're about to be abducted by a UFO. There's fencing set-up on the road to keep the crowds from spilling onto both adjacent pavements, which looks like an unnecessary precaution given the dire turnout, and the big screen at the side of the stage is conspicuous in its superfluity. The chanteuse on stage waves her arm gamely in order to encourage crowd participation and is greeted with nonchalance and half-hearted padam padam-ing for her troubles. It's a sorry state of affairs for an icon supposedly so cherished by the masses, and speaking of masses, where are they all?

It feels like a party nobody has turned up to. As a spectacle it's an insult to the memory of one so supposedly adored. Is this an aberration, or in 50 years from now when the centenary comes around, will Piaf be a forgotten institution who means nothing to the people any more?

"Well that would be sad," says British singer and Piaf devotee, Anna Calvi. "I hope that isn't the case. There are waves of interest in people that come and go aren't there? You never know what it'll be that might spark it off again and I'm sure she'll endure time because I think her voice is so individual and I don't think there's been anyone like her since really."

Calvi isn't a francophone yet, though she spends a lot of time in la Republique these days given that her records do so well here. There's something romantic and passionate about her music that the French tap into, and her interest in La Môme certainly hasn't gone unnoticed. The singer says she identifies strongly with Edith partly because of her stature: "She was so small and yet she had this really big voice, and I'm small. It's nice to feel that even if you're small in one way you can carry this voice and be heard among all the tall people. I always liked that about her."

When Calvi started singing - quite late in the day she says - she remembered Piaf's passionate voice from records played during her childhood and she took them as a source of inspiration.

"I learnt a lot about delivery listening to her records and how you can sing in a language that the audience has no idea what you're saying but you still convey a lot through the power of delivery; the pure emotion of the voice, which she had in spades."

What about the music though? It sounds so antiquated, which it might well deserve to given that it was all recorded 50 years ago or more (she first recorded in 1935).

"I suppose in a way the instrumentation behind the songs is quite old fashioned but then the way she sings is quite punk to me. It's not pretty, it's very confrontational. It's definitely not like the woman behaving herself and being nice, and a lot of it is pretty ugly. In that way I think she's relevant and someone to look up to now because she's got some attitude."

Where Calvi compares Piaf to punk, French singer Lescop draws equates Piaf with US indigenous folk.

"I like her," he says. "Why, because I think the equivalent of country music in America is Edith Piaf in France. In Nashville people say a good song is three chords and the truth, and with Piaf it's not necessarily three chords but she really delivers the truth and means what she sings. She didn't write a lot of her stuff but the words were the truth in her mouth."

Lescop reveals he was listening to a lot of Piaf when he was writing his self-titled debut album, though she wasn't a direct influence being such a sacre monstre: "For me Piaf is like the walls of my apartment. I heard about her when I was a kid and she's really important as a part of French history. For every kid who's into hip hop, they still know who she is."

Piaf's importance is impressed upon me by everyone French that I speak to.

"She was the first French singer to sing abroad and the way she interpreted songs was very special," states Clémence Quélennec from La Femme, "she was a very special person", while Sebastien Tellier adds, "she was super important I think. She laid a deep blueprint. Andy Warhol we know for his beautiful colours but where is the emotion? There is no emotion. With Edith Piaf, she changed the picture we have of a love story, she changed that for the French people. And winning the world also! She was a super artist from my point of view."

Benjamin Schoos, from Brussels, concurs: "She was very famous in Belgium, her life was like a film! Belgians like storytelling. If you talk about chanson Française, Belgians love Jacques Brel (of course he's a Belgian) and Piaf."

Does her voice resonate with Schoos?

"Yes, I like her voice a lot. Some songs are very scary and the lyrics are very sad and sometimes depressing. When I was a child I tried to escape her music, putting my fingers in my ears. Too much emotions and bad feeling!"

Is her appeal diminishing with young people I wonder? "Yes I think so, it's quite sad," he offers, but he takes a similar line to Calvi regarding the fickleness of fashion.

"15 years ago Bob Dylan was an old used-up hippy whereas today he's a God again. Times they are a'changing. Right now it's the same with Fleetwood Mac. Maybe Piaf will be the new phoenix of French popular music in 2025. Fashion sucks."

"I don't know if young people still listen to her," admits Clemence, "but you know on the radio and television you still hear about her and people still cover her songs. She's still important in France for musicians today [if not for young people] and in that sense she's still a big influence."

"It's too old now," laughs Tellier. "Sometimes I might hear her on the radio driving in my car, and of course I connect with the song - with her songs it's always a pleasure - but I wouldn't have an Edith Piaf CD in my player because she's too old and I want to listen to something new."

When I suggest to Lescop that young people aren't in tune with the singer, he's dismissive.

"I don't really care about that," he scoffs. "I understand why a 20-year-old girl might not be interested, but I think she's the kind of singer you can appreciate when you're maybe a little bit older. I'm 35 and I've had some experience and maybe the lyrics of Piaf, the way she sings, reminds me of some of those experiences. When I was 20-years-old I was into Nirvana or David Bowie and an interest in Piaf came later."

Though the late chanteuse obviously had a tumultuous life, Anna Calvi plays that part of her identity down, saying "it feels slightly reductive when singers have to talk about their emotional life because their message as a singer or an artist isn't quite good enough, and so that's something I don't choose to focus on. That was something I found frustrating about the film [La Vie En Rose] that came out about her - it was all about her losing in love and being heartbroken. It's a part of it but it's really limiting to just focus on that."

Young singer Marc Desse, who comes from the western suburbs of Paris, sees the singer's legacy as indivisible from La Belle Epoque, which history remembers as ending with World War I, a year before Piaf was even born.

"Edith is definitely outdated and a symbol of most of the clichés that foreign people adore about Paris, but she's still as major a monument of French culture as Monet, Utrillo, Mistinguett, Brassens, Yvette Guilbert and so on. Parisians like this time and cherish it in a nostalgic way."

Mike Levy, aka Gesaffelstein - Lyon-born banging techno master and Kanye West collaborator - is most effusive in his assurance that Piaf's legacy will not endure. His studio is situated within throwing distance of Bernard's little museum, though he looks disinterested when I tell him this.

"In France the image we have of her is really old. We know she's big but it's more as a character than as an artist. You've got to respect her, the young people respect her, but I don't think they care about her music. She's like Charlie Chaplin - everybody knows Charlie Chaplin or Edith Piaf, you respect the idea that they were big but at the same time you don't care about them. I think in 50 years time we're going to forget her."

What about Gainsbourg, whose image I encounter all the time in Paris, an artist who very broadly speaking it could be argued usurped Piaf as some kind of people's champion?

"Gainsbourg is completely different," he says, "because today his music is still the best music in variété, in French music. I mean, today French singers, they try to do something new, but for me Gainsbourg killed the French scene, totally. He took the book and closed it. We have nothing to do in French music, with lyrics and with music."

Does Sebastien Tellier agree that Piaf will be forgotten in half a century's time?

"Oh yeah, for sure, but for me it's the same as Jesus or Michael Jackson or Elvis even, the biggest guy in music. If you want longevity you have to be a political guy, you know, like Genghis Khan, but if you want to be eternal and you're an artist it's no good. You might last longer than you realise, maybe two centuries if you're the best ever, but two centuries is nothing in the great scheme of things. I don't have to sacrifice my life for this bullshit, because one day people will forget."

When I mention Gainsbourg to Sebastien he prophesies that "in two decades [Serge] might still be fresh, but in three centuries he will be forgotten."

"She will not die because politicians are a very strong force maintaining cultural standards," argues Marc Desse about Piaf. "Don't forget that Paris is a 'Museum city'."

"Yeah yeah, people will still like her," opines Lescop. "I don't know, if you asked someone who doesn't like her they'll say 'no', if you ask someone who does like her they'll say 'yes'".

It's a fair point, and we'll not know anything conclusive for another five decades, though it won't stop us speculating. And so the last word falls to Jean Cocteau from beyond the grave: "Art produces ugly things which frequently become more beautiful with time," he once said, while "fashion, on the other hand, produces beautiful things which always become ugly with time." Hopefully that clears it up for you.