The most basic division of society was between the three estates. The First estate, about 130,000 people out of a population of 27 million, was the clergy. The Second Estate, about 350,000, was the nobility. These were the aristocrats. Between them, the first two estates controlled the government. Finally, there was the Third Estate, made up of the commoners.
Within the Third Estate, there were different types of people and these might be called divisions in society as well. There were the peasants, skilled artisans and shopkeepers and such, and finally the wealthiest of the Third Estate, people like important merchants and bankers.
These were the basic divisions of France's society on the eve of the Revolution.