Sébire lived in Plombières-lès-Dijon, near Dijon, France, and was the mother of three children. In 2000, she was diagnosed with esthesioneuroblastoma, a rare form of cancer of which only 200 cases have been reported in the past 20 years. Sébire refused any treatment at the time of her diagnosis, not wishing to take the risk of the surgery or medications. With time, the cancer burrowed through her sinuses, nasal cavities, and eye socket, leaving her face severely disfigured. She had also lost her sense of sight, taste, and smell and suffered with severe pain that she was unable to relieve with morphine due to its side effects.
Sébire first gained recognition in February 2008 when she made a public appeal to the French president, Nicolas Sarkozy, to allow her to die through euthanasia, stating that "One would not allow an animal to go through what I have endured.". On March 17 2008, she lost her case in a French court, with the magistrate noting that while French law does allow for the removal of life-support equipment for terminally ill patients, it does not allow a doctor to take action to end a patient's life. After the decision, Sébire said "I now know how to get my hands on what I need, and if I don't get it in France, I will get it elsewhere".
On March 19, 2008, she was found dead in her home. An autopsy conducted on March 21 2008 concluded that she did not die of natural causes. Subsequent blood tests revealed a toxic concentration of the drug Pentobarbital, a barbiturate that is not available in French pharmacies but is used elsewhere in the world for the purpose of physician assisted suicide.