What is suggested by the coin image in Book II of A Tale of Two Cities?

The scene in Book the Second, Chapter 7: Monseigneur in Town centers on a fancy reception with lots of French aristocrats in attendance. The upper-crust gathering is taking place at the Parisian suite of a French Lord, Monseigneur. One of the partygoers gets miffed by the lack of attention he's paid by the other guests and the host, so he leaves in a huff in his horse-drawn carriage.

Self-absorbed and arrogant, the Marquis St. Evrémonde lurches recklessly through the Paris streets. Along the way, the Marquis's carriage runs over and kills a child. Unmoved by the accident, the Marquis flippantly tosses a coin to the boy's grief-stricken father as he approaches the carriage. To a member of the wealthy ruling class, a coin would be more than payment enough for the death of a valueless peasant kid.

As the carriage moves forward away from the crowd that's assembling, the coin is tossed back at the Marquis in defiance of his haughty, hateful behavior. Angered by the ungrateful nature of the lower class, the Marquis spews threats before hurrying off. The coin, in its simplest form, represents the defining difference between those that have