When we are first presented with Madame Defarge, she is knitting quietly in the wine shop. However, this knitting hides the bloodthirst that we see later on in the novel as we discover that behind this mask of passivity lies a real desire for vengeance, for she is secretly knitting with her stitches a register of the names intended for slaughter as part of the revolution. In particular, Darnay's association with the Evremonde family and Mdame Defarge's special link with this family means that she takes a particular relish in condemning both Charles Darnay and his wife to death. We see her committing the faces of Lucie and her family to memory, and then invades the house of the Darnay's to try and catch Lucie before she leaves.
While knitting in a wine shop at the beginning of A Tale of Two Cities, Madame Defarge, the anti-hero of the novel, is quietly recording the names of people who will later be the victims of revolutionary zeal during the French Revolution. She is the perfect spy, as she says nothing but sees everything, and she keeps her boiling resentments hidden until it is the right moment to attack her victims.
Her hatred of aristocrats, which she carefully notes in the wool she uses to knit, stems from her family's history with the Evremonde family, which was Charles Darnay's title before he relinquished it. Her sister was kidnapped by Charles's uncle, also an Evremonde, and her father died of sadness as a result. Charles's family, including his wife Lucie and daughter Lucie, have long been on Madame Defarge's list of intended victims. Madame Defarge is symbolic of the French working class's desire for vengeance after their long years of suffering at the hands of aristocrats.