The cause for the French Revolution was, as usual, economic. Most unfortunately,
since France financed the American Revolution, it really drained France's banks.
The effect of the French Revolution was horrible. A liitle-known fact is that Antoine
Lavoisier, the father of modern chemistry, was guillotined because of his political
ties. Roman Catholic priests and religious were also guillotined because they were loyal to the Pope and not to the civil authorities. The only good that came out of it was the metric system.