This master’s thesis builds up on Baubeau’s database of the Banque de France published balance sheets (1840-1998). We used alternative primary sources –The “Situations générales de la Banque de France” (internal daily balance sheets ledgers) and the “Situations générales des succursales” (internal ledgers of the branches weekly balance sheets)– to fill gaps and improve the database. We extended the database from the creation of the Banque de France in 1800 to 1839. We also collected the data to fill the gaps for annual series by constructing a balance sheet for 29/12/1870 and 31/12/1914. Moreover, we clarified the reason behind an oversized “Sundry assets” item in the published balance sheets from October 1926 to June 1928. One of the main purpose of this work is to explicit the methodology used to complete and improve the database so that the users of the database use it fully aware of the limits of the source, and maybe carry on the yet unfinished work of improving the database and its metadata.