There are three causes of French Revolution.They are: political ,social and economic changes.

Political Causes:-

1) There was absolute monarchy in France.The king ruled without any control.
2) The French people didn't have any political right like forming union,organisation etc.
3) people and press didn't have any freedom of speech and expression.

Social Causes :-

1)The French society was divided into three states - first state ,second state and third state.
2) the first and second state comprised of royals,noblesand clergy.They enjoyed all privileges of society.
3) The third state comprised of workers,labourers,small traders,farmers,etc.they didn't enjoy privileges of society.
4) The first and second state constituted 10% of French population while the third estate constituted 90% of population.
5) The first and second state enjoyed high social status in French society while the third estate was having low social status.

Economic Causes:-

1) The royal treasury of France was empty as French government was supporting the freedom fighters of American war of independence.
2) The king Louis XVI has increased the taxes.only third state people had burden of paying taxes.
3) The king and queen were living a luxurious life.
4). The condition of agriculture and Industry was bad.
5). French people were neither getting food nor work.It resulted subsistence crisis for common people.
6) The subsistence crisis for majority of people forced them to revolt.



Hope this answer helps you.
The answer is a little bit long because the question is also long.

There are 5 causes of French revolution -
(a) Political cause
(b) Social cause
(c) Economical cause
(d) Intellectual cause
(e) Immediate cause