Why was treasury empty when Louis 16 a rounded the thrown
Answers
“Empty” is an exaggeration - but the French Crown was in financial difficulty.
Debt was high - in spite of the “bankruptcy of two thirds” (defaulting in two thirds of the debt) by the previous King, Louis XV. Indeed borrowing was very expensive for French Kings, in terms of interest rates charged, because the French monarchy had a record of defaulting on some of its debts (unlike the British constitutional monarchy - which did not have this reputation, and so was charged lower interest rates on its borrowing).
French Kings had led France into very expensive and, basically, unsuccessful wars - the victories of Britain in places such as India were the defeats of France, losing wars has consequences. Also the French taxation system was badly organised - it is not true that the nobility were immune from all taxes, but they were immune from most taxes. And the implied bargain was that French nobles would stay out of trade and industry - unlike British nobles who did pay the land tax, but were under no implied obligation to stay out of trade and industry (indeed in 18th century Britain the big landowners, mostly aristocrats and gentry, provided the investment for a lot of industry - from the profits of their landed estates).
Also taxation in France was (in most of the country) controlled by tax “farmers” who kept some of the money they collected - the British tax collectors were paid a wage and that was about it. And the very economy of France was weaker - it was dominated by guilds (as it had been since the edict of King Henry IV in the early 1600s) there was just relatively less trade and industry in France (in proportion to the population - France did have a large population than Britain) to provide wealth to be taxed. And French farming was, generally, less advanced than British (at least English) farming - again providing less wealth to be taxed.
Short version - the economy of France was (generally speaking) less advanced than that of Britain and the administration of France was not very good, the taxation system was too complicated and not really under direct government control. The King was like a prisoner in a golden cage - the Palace of Versailles, without (unlike Britain) there being a real government responsible to a Parliament in France. In theory the French King could do almost anything - but he was not a politician or an administrator, the Kings of France had become trapped in the webs of ritual and bureaucracy that had been spun by Louis XIV (the “Sub King”) a century before.
However, the situation was bearable - till Louis XVI tipped things over the edge by giving into demands that France support the American War of Independence - France won that war, but winning wars sometimes is almost as expensive as losing them.
he spend his money in helping 13 colonies of America and he involved him self World War 2