The former nurse of aged French L'Oreal heiress Liliane Bettencourt was found not guilty of exploiting the frail billionaire on Monday, nine months after trying to hang himself on the eve of the trial.
The prosecution accepted there was insufficient evidence to prove that Alain Thurin, 65, abused Bettencourt's trust to get her to include him in her will.
Thurin tried to commit suicide the day before the trial began in January. He later told the court he had grown very close to Bettencourt, now 93, and never wanted her money.
A bequest of 10 million euros ($11 million) to Thurin has since been removed from her will.
He was one of 10 people accused of exploiting Bettencourt's failing mental health in an explosive legal and political drama that even dragged in former president Nicolas Sarkozy.
"No testimony or material evidence shows the desire of the accused to take money from Liliane Bettencourt," said the judge in the Bordeaux court as he acquitted Thurin.
The former nurse had his trial delayed after the suicide attempt, and was in a weakened state when he finally appeared before the court this month.
Seven people were found guilty in May, including Bettencourt's close confidante Francois-Marie Banier, a 67-year-old photographer who is godfather to actor Johnny Depp's daughter.
Banier was sentenced to three years in prison and ordered to repay 158 million euros.
Two others were given 30-month sentences and 250,000-euro fines, while the rest received lesser sentences. All seven have appealed the verdicts.
The complex saga began in 2007 when Bettencourt's daughter Francoise filed charges against Banier for exploiting her mother's frailty after the death of her father Andre.
Several members of her entourage were secretly recorded by Bettencourt's butler, who had grown increasingly concerned about her mental state.
Bettencourt was declared unfit to run her own affairs in 2011 after a medical report showed she had suffered from "mixed dementia" and "moderately severe" Alzheimer's disease since 2006.
One of those convicted, Patrice de Maistre, who managed her vast fortune, was accused of getting Bettencourt to hand over envelopes of cash to members of the conservative UMP party during Sarkozy's 2007 presidential campaign.
The charges against Sarkozy were dropped in October 2013 due to lack of evidence, and one of his ministers was also cleared of wrongdoing during the trial.
Bettencourt's father Eugene Schueller founded L'Oreal in 1909, starting with hair dye and later branching out to form the world's largest cosmetics company, famous for the advertising slogan "Because I'm Worth It."