As you might expect, the film is about Edith Piaf. In the film she is presented as someone who isn't entirely in control of her life and as someone who move from one catastrophe to another. She lived with an alcoholic mother before living with an alcoholic grandmother. She was packed off from her grandmother's by her (soon to be) abusive father who dumped her in his mother's brothel for a few years. When he came to pick her up, he quit jobs and effectively lived off his 9 year old daughter's singing voice (she had a pair of lungs on her, trust me when I say that).
When she left home, she was 17, and was still singing to support a family but was living on the street. Soon after she left she had child, only to see the child die aged two and fell in with a pimp who would later kill her first manager (a man who had brought her a degree of success), a killing she would be accused of being involved in.
After the death of her manager she went into a tailspin and became a borderline alcoholic. She was largely saved from this, by her second manager, but her woes didn't stop there. For example, a road accident almost killed her and contributed to her getting addicted to heroin and her lover was killed in a plane crash while he was coming to see her.
By the time she was 47, it isn't surprising that she looked closer to 75 and had the posture of an 80 year old. She lived hard and died comparatively young because if it.
It was a good film, but it got to be a bit like watching a train-wreck waiting to happen after a while, you started to wonder what possible catastrophe could befall her, only to have your expectations exceeded when the next tragedy occurs. In short it's beyond depressing.
Incidentally I was struck by how much Souxsie Sioux from Souxsie and the Banshees looked like Edith Piaf during the film. I'm not entirely sure if everyone agrees with me, but trust me when I say that the similarities are there.