Sachs, best known for his glamorous lifestyle and for marrying French icon Brigitte Bardot in the 60s, was found in his chalet in Gstaad, a glitzy alpine resort that is home to many VIPs and celebrities.
He was suffering from an incurable degenerative disease, thought to be Alzheimer's, and died from a gunshot wound to the head, according to Swiss and international reports.
Sachs' relatives released a suicide note to Swiss media in which he explained he took his life because of an illness he dubbed "A."
"The loss of mental control over my life was an undignified condition, which I decided to counter decisively," the letter signed by Sachs said. He called it the "no hope illness A," Swiss news agency SDA reported.
Sachs gained fame for his work as an industrialist, film-maker and photographer, and for marrying Bardot in Las Vegas in 1966 in his second marriage. They got a divorce after three years and Sachs re-married. He had three children.
He lived for years in the Swiss village of St. Moritz, contributing to the resort’s exclusive image, and became a Swiss citizen in 1976, reports said. Later in his life, he developed a passion for astrological research, commissioning studies on the correlation of the stars and human behaviour.