While she remained in the background most of her life, Mrs. Bettencourt had long tried to live down the stains of anti-Semitic activities and Nazi associations by her father and husband before and during World War II: a well-documented record of propaganda writings and material support for fascist groups, some of whose followers found refuge after the war at L’Oréal.

Regal, extroverted, a tireless socialite who loved balls and dinner parties, jewels and haute couture, Mrs. Bettencourt was ranked by Forbes this year as the richest woman in the world, with her net worth put at $39.5 billion. She was the majority shareholder of L’Oréal, the world’s largest, most powerful cosmetics company.

She was the only child of Eugène Schueller, a chemist who, in the kitchen of his Paris apartment in 1907, created a hair dye he called Auréale. His business, renamed L’Oréal in 1939, acquired Lancôme, Maybelline, Helena Rubinstein, Giorgio Armani and other brands, creating a giant that employs more than 77,000 people in 130 countries, had revenues of almost $26 billion in 2016 and is a prestigious economic engine for France.

Liliane grew up in a cocoon of privilege and secrets. Her father was a Nazi sympathizer who acquired property taken from Jews in Germany, supported a French fascist organization in the 1930s that met at L’Oréal’s Paris headquarters, and founded a wartime movement against Bolshevism, Judaism and the Freemasons. He was spared from prosecution as a collaborationist by the intervention of political allies, including his future son-in-law, who claimed he had joined the Resistance and saved Jews.

In 1950, Liliane Schueller married André Bettencourt, the scion of an old Norman Roman Catholic family. He had been a virulently anti-Semitic propagandist early in the war — a role hidden most of his life behind the sanitizing record of his Resistance exploits in the final stages of the war. For these, he was awarded the Croix de Guerre, made a chevalier of the Legion of Honor and promoted as a war hero in a political career that lofted him to prominence as a cabinet minister in several governments.

Mr. Schueller died in 1957, leaving his daughter billions and his controlling interest in L’Oréal. She became a director, but took a largely passive role as her father’s successors expanded the company around the world, ballooning the value of her holdings.