Final answer:
The Peasants, who were part of the Third Estate, paid about half of their income in taxes, bearing the most significant tax burden prior to the French Revolution.
Step-by-step explanation:
The group that paid about half of their income in taxes was the Peasants. During the period leading up to the French Revolution, the burden of taxes fell mostly upon the Third Estate, which consisted of the common people, including the peasants, urban poor, and the bourgeoisie. The First and Second Estates, the clergy and the nobility respectively, enjoyed various privileges, including exemption from taxes or paying very little towards them. In contrast, the peasants shouldered a disproportionate amount of the tax burden, sometimes paying as much as 50% of their income in taxes.