A few important symbols in A Tale of Two Cities include the wine cask breaking, the knitting and the guillotine.
The wine cask breaking at the beginning of the novel leaks wine all over the cobblestone. The peasants run to the cask scooping up the wine, celebrating together in the streets and then just as quickly as it began, it stopped. The peasants are reduced to animals in the scene "tigers" violently lapping up as much wine as they can. One peasant uses the wine to smear the word blood on the wall. The imagery in this chapter illustrates the energy, violence and hunger of these peasants. It shows the peasants need to get rid of their physical hunger, but there is a deeper hunger here. These people are all able to come together in a nonviolent way to drink the wine. There is no competition among them. Beyond that, this scene foreshadows the impending bloodshed. The scene obviously pairs with the sharpening of the swords later on in the novel. It thematically connects to the idea of mob mentality as being both treacherous and dangerous.
The knitting is a recurring image throughout. Although primarily done by Mme Defarge, other women are also shown knitting in the novel. Mme Defarge knits a registry of the people who will be killed by the revolutionaries. With the addition of children, women, and men not connected to their cause, this registry symbolizes the blood-thirsty and vengeful nature of the revolutionaries. The knitting here also alludes to the Fates of Greek mythology who controlled human destiny through their weavings. Thematically, this connects to the characterization of the revolutionaries as vengeful and cold-hearted. The actions by the nobles that the revolutionaries condemned are merely repeated by the revolutionaries thanks to the notes on the registry.
The guillotine is also an important image in the novel as it represents equality to the peasants as men and women who have denied them basic human rights are killed before them. To those who were not revolutionaries, it represented terror and fear as no one knew who would be the next to be accused and killed by the weapon - very very few were found innocent after being accused.