Alain Thurin, 64, her former nurse, hanged himself in the woods on Sunday near his house and was in critical condition on Monday.
He is one of those accused of exploiting the L'Oréal heiress's growing mental fragility in a scandal which erupted in 2007.
At one stage former president Nicolas Sarkozy was accused in connection with the trial but later acquitted.
Amongst allegedly unscrupulous friends and politicians is François-Marie Banier a celebrity photographer, Patrice de Maistre her fortune manager and Eric Woerth a former minister and campaign treasurer for ex-president Sarkozy.
In 2011 Bettencourt was declared unfit to run her own affairs after a medical report showed she had suffered from "mixed dementia" and "moderately severe" Alzheimer's disease since 2006.
The trial was suspended on Monday shortly after it began to allow the court to study a procedural issue raised by the defence and will resume Tuesday.