A normal solider of the line was paid 30 centimes per day. During peacetime at garrison, the soldier had to pay for most of his food. On a war footing, he received his field rations on top of his pay. When he was on the march, he received his pay plus his ration of pain de munition. If a soldier went into hospital or the guardhouse (jail) or on extended leave, his pay was reduced.

Specialists, like grenadiers, carabinier, voltigeur, sapeur d'infantrie, cuirassier, carabiner a cheval or artillerymen all drew higher pay. Long service bonus of 100 centimes (1 franc) was paid a month after 10 years continuous service. 15 years of service would net him 1.5 francs and 20 years, 2 francs extra a month. There was also a bonus of 50centimes a day if he was required to work on fortifications. Troops stationed in Paris and Northern Italy drew special allowances for increased cost of living.

At the end of the day, 30 centimes is whittled down to 5 centimes a day after stoppages (food/uniform/washerwoman/upkeep) to spend on tobacco/wine/women/games.

Source - Swords around a Thrown: Napoleon's Grande Armee - by J R Elting