L'Oreal heiress Liliane Bettencourt, the world's richest woman, has died at the age of 94, her family said today.

'Liliane Bettencourt died last night at home,' her daughter Francoise Bettencourt Meyers said in a statement. 'My mother left peacefully.'

Bettencourt, the cosmetics giant's principal shareholder, was the 14th richest person in the world, according to Forbes magazine, which estimated her net worth in March at $39.5bn (£29.1bn).

She was rarely seen in public since leaving the L'Oreal board in 2012, but her name remained in the headlines as members of her entourage were charged with exploiting her failing mental health.

Bettencourt had been declared unfit to run her own affairs in 2011 after a medical report showing she had suffered from 'mixed dementia' and 'moderately severe' Alzheimer's disease since 2006. The complex legal case involved a bitter feud with her only daughter and unscrupulous friends, and even dragged in former president Nicolas Sarkozy.

Patrice de Maistre, who managed Bettencourt's vast fortune, was accused of getting her to hand over envelopes of cash to members of Sarkozy's right-wing UMP party during his 2007 presidential campaign.

The charges against Sarkozy were dropped in October 2013 due to lack of evidence. Bettencourt was born Liliane Schueller in Paris in 1922 to L'Oreal founder Eugene Schueller and Louise Madeleine Berthe - who died when Bettencourt was just five years old.

She started working for L'Oreal aged 15 as an apprentice labelling bottles of shampoo and rose through the ranks over the years. 

She married French politician and future cabinet minister Andre Bettencourt in 1950, the couple remained together for 57 years during which time they had one daughter.

She inherited L'Oreal after her father died in 1957 and remained at the helm of the company for more than five decades.