Bardet was born as Marie-Thérèse Louise Jégat in Lorient, Brittany, France on 2 June 1898 to housemaid and single mother Marie-Louise Jégat. Her mother sent her to state care at a young age. She survived typhoid fever aged 15, and worked on a farm during World War I.
Bardet married her husband, Léon, a shipyard worker, and had two children, Léon Jr. and Jeanne, in 1922 and 1924. She was widowed in 1953, and lived with her son until 1982, when she moved into a retirement home in Saint-Nazaire, Pays de la Loire. In 1990, she relocated to another Pays de la Loire retirement home in the commune of Pontchâteau, where she lived for the rest of her life.
By the age of 112, it was reported that Bardet’s speech and hearing had deteriorated, but was still mentally sharp, enjoying seeing pictures of her newborn great-great-grandchildren.
On her 114th birthday, Bardet had seven grandchildren, 15 great-grandchildren, and six great-great-grandchildren. She died on 8 June 2012, six days after turning 114, as the seventh-oldest person in the world.