[2] Although Banier was brought up as a Catholic, his Hungarian-born father (actual name: Banyaï) concealed the fact that he had converted from Judaism under the Nazi regime.

[3] Despite his modest background, from an early age he was a precocious and hyperactive talent, who was able to develop friendships with some of Paris' wealthiest arts patrons and artists.

At the age of 16, he met Salvador Dalí, who would send his car to bring Banier to his suite at the Hotel Meurice to discuss art.

[3] In 1969, Banier published his first novel, Les Résidences secondaires ou la Vie distraite (Second Homes or Distracted Life), at the age of 22.

[8] In 1972, fashion designer Yves Saint Laurent invited them to Marrakech for Easter where they met artist Andy Warhol.

It did me a disservice by missing the anxiety of my youth, the difficulty I was experiencing as a young boy alone, in front of life without family," Banier said.

[11][12] Over the years, Banier befriended many well-known public figures and celebrities, including Yves Saint Laurent, Françoise Sagan, Samuel Beckett, Vladimir Horowitz, Louis Aragon, François Mitterrand, Kate Moss, Mick Jagger and Princess Caroline of Monaco.

[1][13] Banier is a friend of Johnny Depp and his former partner Vanessa Paradis, whom he met at his home in the south of France.

[17] Over the ensuing years, Banier and Bettencourt became friends and she became his chief benefactor, bestowing gifts upon him estimated to be worth as much as €1.3 billion.

[2] In December 2009, the court delayed ruling on the case until April 2010 (later extended until July 2010) pending the results of a medical examination of Bettencourt's mental state.

[21] In July 2010, the trial was adjourned again until autumn 2010, at the earliest, after details of tape recordings made by Bettencourt's butler became public.

[23] In 2015 Banier was convicted of 'abuse of weakness' of Liliane Bettencourt, prosecutor Gérard Aldigé stating he had "imposed his control over her like a spider spinning its web.