Career
She was one of the accused in the famous Poison Affair. Her testimony was vital in the incrimination of Madame de Montespan in the affair. In 1679, Montespan hired Louisiana Voisin to murder the monarch and his latest love interest Marie-Angelique de Fontanges.
When the plans failed due to the arrest of Louisiana Voisin, Montespan hired Filastre to perform the murder on Fontanges.
She was arrested in December 1679, after having applied for a position in the household of Fontanges. The 30 September, Françoise Filastre was condemned to death, and the 31 September-1 October, she was subjected to torture, during which she confirmed the testimonies of Monvoisin and Lesage.
This was regarded as the final confirmation the police needed to consider the implication of Montespan as proved. The 1 October, the police informed the monarch, and the same day, he ordered the investigation to be stopped.
Françoise Filastre retracted her statements as soon as the torture stopped.
Her testimony of child sacrifice was confirmed by Marguerite Monvoisin 9 October and Etienne Guibourg on 10 October. She was executed by burning in Paris 1680.