Warens was born in Vevey, into a Swiss Protestant family who had immigrated to Annecy, but became a Roman Catholic in 1726 in order to receive a church pension which had been instated to increase the spread of Roman Catholicism near Geneva, then a bastion of Protestantism.
She annulled her marriage to M. de Warens in 1726 after failing in a clothing business.
It was said that she was a spy and a converter for Savoy, then part of the Kingdom of Sardinia.
Though Warens was originally a teacher to Rousseau, they became sexually engaged after she openly initiated him in the matters of love and "intimacy".
Françoise-Louise de Warens died in poverty in 1762 in Chambéry, of which Rousseau did not learn until six years afterwards.