"Everything went smoothly" – a 67-year-old man awaiting trial for the robbery of reality star Kim Kardashian in Paris four years ago has come clean in a new book, laying out the life history that led to his involvement in the heist.

Yunice Abbas, who calls himself a "part-time crook," was one of 12 people arrested for nabbing a small fortune in jewels after surprising Kardashian in the luxury residence she rented to attend Fashion Week.

As his book's title makes clear – I Kidnapped Kim Kardashian – Abbas has no plans to contest the charges at a trial prosecutors are hoping will begin this year.

Kim Kardashian.

It was the biggest robbery of an individual in France in two decades, with the thieves making off with a combined haul worth about nine million euros.

Most of the pieces were never found: police have recovered only a diamond-encrusted cross that Abbas dropped while leaving the scene by bike.

"The jurors will have to decide, and in theory they'll do it based only on what's presented to them in court, but 50 stories have already been told about all this – I wanted to tell my truth, the one I've lived," Abbas told AFP.

He was one of five men aged 60 to 72 – dubbed the "Grandpa robbers" in the press – who entered Kardashian's apartment at around 2.30 am on the night of October 3, 2016.

The star later told police the men, at least one of whom was wearing a jacket with police insignia, tied her up with plastic cables and adhesive tape, and placed her in the bathtub.

'I needed the money' 

"It went fast, maybe five, six, seven minutes, from entry to exit, because everything went smoothly. Nobody interfered, the victim handed over the jewels without resistance," Abbas said.

But as he entered the street alone – he says he was last to leave – he found himself face to face with a police patrol.

"I was shutting the door and they looked at me, so I gave a little sign, like a salute.

Police officers stand guard at the entrance to the hotel residence at the Rue Tronchet, near Madeleine, central Paris, on October 3, 2016, where Kim Kardashian was robbed at gunpoint. Photo: Thomas Samson/AFP

"They were just on one of their rounds, but obviously I was nervous. I looked calm, or at least I tried to, and it worked."

Abbas said that almost immediately he had regrets, and he was one of 12 suspects arrested three months later.

He had spent his life in and out of jail – 21 years in total – but had been "clean" for nine years before being offered the Kardashian heist "at a time when I needed the money", he said.

After 22 months behind bars, a judge released him on health grounds, and Abbas now hopes a jury will be lenient after he underwent heart surgery.

"My fear is returning to prison, my health is no longer good," he said.

"If you have an attack, you might have to wait hours before they can do anything, with catastrophic results."