Question

what was main aim of french revolution?

Answer 1

At first it was to give the Third Estate a right to have a say in the ruling of France and break the absolute power of the monarchy. The dream of the first revolutionaries was to have a monarchy more like the British, with the king (and the nobles) held in check by a parliament and less obligations and more rights for the lower classes. 
Then the moderates got run over by the fanatics as the king did lots of stupid things that didn't help his case (like running away) and the equality for all and a republican state replaced a parliamentary monarchy.