When Louis XVI of the bourbon family of kings ascended the throne of France in 1774, he found the treasury empty. Long years of war had drained the financial wealth of France, adding to this the cost of maintaining an extravagant court the immense palace of Versailles. To meet its regular expenses, such as the cost of maintaining the army, court, running government offices and universities the state was forced to increase the taxes. The increase of taxes ultimately led to French Revolution.
Actually when king Louis 16 summoned for a state assembly ,he asked the 3rd chamber members[people] to agree to rise the taxes in order to face the financial crisis . but the commoners disagreed to do so and king locked the 3rd chamber. This led to the tennis court oath.Though it ended in failure ,it became the reason for the immediate cause which was the seige of bassiles.