The task was relatively simple to perform to the level of an urban district, however it took on a whole different scale in a rural area or across a kingdom.
In 1426, the duke of Brittany made a "reformation of taxes" to limit exemptions (noble families had to prove their nobility) in all the provinces.
Yet their accuracy should be put in perspective: the provinces did not stop asking the central government for revisions, always for reduction, due to famine or epidemic.
The total number of fires was therefore subject to hard bargaining between the central government and municipalities, regardless of the reality on the ground.
In addition, the poorest families were grouped at the parish level as a single fire for joint taxation.
Serge Dontenwill: for the current department of the Loire under Louis XIV, using a coefficient of 4.5 (and following Jacques Dupâquier in his French population in the 17th and 18th centuries, PUF, 1993).