The following is contained in the Historical Dictionary of Napoleonic France edited by Owen Connelly and the entry is written by Harold T Parker, 179-181. It is an excellent summary of the French financial and fiscal system under the Consulate and Empire. Another excellent resource is France Under Napoleon by Louis Bergeron, 37-51:
'Napoleon's chief financial problem was to find ever greater amounts of money for his government, his military forces, and, eventually, his empire. In 1799 he inherited from the Directory a desperate fiscal situation: taxes were not coming in; overdue bills for supplies and salaries of civil servants and soldiers were not being paid; government bonds were selling at 11.38 (par 100); and the government was forced to borrow at 5 percent per month. Bonaparte had no special competence in finance, but he recognized his ignorance of fiscal mechanisms and was willing to learn. He appointed officials from among civil servants trained largely under the Bourbon monarchy. The more notable ones were Michel Gaudin, minister of finances (in charge of collecting taxes); Francois de Barbe-Marbois, minister of the treasury (responsible for payments); and Nicholas Mollien, director of the sinking fund. In the early weeks of the Consulate, by catch-as-catch-can expedients, they and Bonaparte managed to get some money into the till. They then began to build fundamental financial structures.'
'They introduced a rigorous collection of direct taxes (real estate and personal property) by appointing a hierarchy of efficient collectors (percepteurs at the first level, a receveur particulier for each arrondissement, a receveur general for each departement). Eventually these officials were required to pay the taxes into a Service Fund (caisse de service) as they received them. To ensure a fair assessment of real estate taxes, the Ministry of Finances initiated the preparation of a cadastre, a register of the ownership, quantity, and value of every parcel of land in France. Until the disasters of 1812-1813 direct taxes were kept moderate and constant at about 250 million francs annually. To balance the budget, the government levied a variety of indirect taxes (customs duties, stamp and registry dues, excises on the sale of tobacco, liquor, and salt), which could be raised or lowered according to need. Expenses were rigorously monitored. A hierarchy of paymasters in the Ministry of the Treasury paid only those bills authorized by a law, a decree, or the warrant of a minister. An audit commission (cour des comptes) reviewed the bookkeeping accounts of collectors and paymasters. Included in expenses was interest on the old debt inherited from the Directory, which the Consulate in part assumed and in part repudiated. Interest was paid in coin in a new standard franc. A sinking fund (caisse d'amortissement) was established, chiefly to intervene on the bourse (stock market) and by purchase to keep the price of government bonds high.'
'Napoleon strained to have a balanced budget and never to incur a large, standing indebtedness. The budget was presented annually to the Tribunate and legislative body for approval, but only after the budgetary year had begun, and it was often altered during the year. Ratification was sought in effect only for tax levies and not for expenses, which were not detailed. Still, the legislative bodies had a greater role than is generally thought.'
'In years of relative peace (1802 for the Consulate and 1810 for the Empire) the budget was balanced. In expensive war years, it was nearly balanced, until 1812, by quartering troops in foreign lands and by levying contributions on allies and defeated enemies. After Jena, for example, Prussia was assessed an indemnity of 311 million francs. The money and property acquired in this way were placed in a separate fund, the extraordinay domain, under separate administration. A balanced wartime budget thus depended on victory. War expenditures did not bear hard on the French until the defeats of 1812-1813. Very early (1800) the Bank of France was set up, largely to assure French businessmen credit at a reasonable rate.'
'The fiscal result of these measures was a vigorous, durable fiscal administration. The French people were habituated to punctual discharge of their tax obligations. Even during the turbulent, disastrous years of 1814-1815, they paid regularly, to the amazement of the prefects. The government debt had been kept moderate and could be assumed without great distress by the Restoration monarchy. The new franc de Germinal was stable and in 1811 commanded a better exchange rate than the pound sterling. The market price of government bonds rose from 11.38 (November 1799) to 93 (summer 1807), though it declined after the invasion of Portugal and Spain. A form of annual legislative review had been introduced into the budgetary process. A central bank had been brought into existence. If Napoleon did not understand the advantages of public credit in financing a war and peacetime projects, at least he knew its dangers. He tried to run a tight financial operation, and in the process he kept his own regime going and founded structures that endured.'
Some other sources:
https://www.napoleon.org/en/magazine/interviews/pierre-branda-on-napoleon-and-money/
https://www.cairn.info/revue-napoleonica-la-revue-2008-3-page-2.htm