Would a conscription/army officer arrive in your village in rural France ahead of one of Napoleon's campaigns and order all young able-bodied males to come forth? Or was it an ongoing process throughout the year, where names of young men in each town/village were regularly drawn from a hat?
Was the process different or the same for men in cities vs men in rural towns/villages?
Although more can be said, /u/waldo672 covered a similar question in their answer