Issei Sagawa, a Japanese murderer known as the "Kobe Cannibal" who killed and ate a Dutch student but was never jailed, has died aged 73.

Sagawa died of pneumonia on 24 November and was given a funeral attended only by relatives, with no public ceremony planned, his younger brother and a friend said in a statement.

In 1981, Sagawa was studying in Paris when he invited Dutch student Renee Hartevelt to his home.

He shot her in the neck, raped her, and then consumed parts of her body over the course of several days.

Sagawa then attempted to dispose of her remains in the Bois de Boulogne park and was arrested several days later, confessing his crime to police.

But in 1983 he was deemed unfit for trial by French medical experts and was initially held in a psychiatric institution before being deported to Japan in 1984.

Hartevelt's family pledged at the time to push for Sagawa to be prosecuted in Japan so that "the murderer would never go free".

But on his arrival, he was ruled sane by Japanese authorities, who decided Sagawa's only problem was a "character anomaly" and that he did not require hospitalisation.

Japanese authorities were unable to get his case files from their French counterparts, who considered the case closed, leaving the murderer to walk free.

Sagawa made no secret of his crime and capitalised on his notoriety, including with a novel-like memoir titled "In the Fog" in which he reminisced about the murder in vivid detail.

The murder was also the subject of Japanese novelist Juro Kara's "Letter from Sagawa-kun", which won the country's most prestigious literary prize in 1982.

Despite the heinous details of the murder, and his lack of remorse, Sagawa gained a level of celebrity and regularly gave interviews to domestic and international media in the years after his return.

He was featured in a magazine for his paintings of naked women, appeared in a pornographic movie and produced a manga comic book that depicted his crime in graphic and unrelenting detail.

The sordid fascination with the murder even saw it referenced by the Rolling Stones and The Stranglers in songs.

Sagawa lived out his final years with his brother, reportedly in a wheelchair after a series of health problems including a stroke.

But he displayed no apparent sign of remorse or reform, telling Vice in a 2013 interview as he looked at posters of Japanese women: "I think they would taste delicious".

He also recounted details of the incident and his ongoing obsession with cannibalism in interviews and a 2017 documentary, "Caniba".

The film's directors spent months with Sagawa and his brother, and described themselves as "conflicted" about the experience.

"We were disgusted, fascinated, we wanted to understand," said co-director Verena Paravel.