Thanks, Alexander, but since 1808 a full strength company was to have 121 privates plus 8 caporaux, means ideally 129 men in rank and file:Marshal Davout estimated in 1811 that the frontage of a section is equal to 8 meters or 12 paces (the "metric" French pace is 2/3 of a meter).
Two sections is a peloton of 99 men in three ranks. So, according to marshal's estimation, one man occupied about 0.5 meter in the rank.
http://www.institut-strategie.fr/N_5_7.html
In three ranks, these 129 men give 43 files, or 22 files per section (I don't know why it is not 132 men, which - under ideal peace time conditions - would result in two equal sections). Even if we assign only 50 cm to each man, the frontage of the full strength peloton would be 11 meters.
Therefore I think that Davout chose 8 meters or 12 paces for his "bataillon de cordes" for convenience, just because it is easy to calculate in meters and in paces.
11 meters and 16,5 paces, or 14,6 meters and 22 paces, would have been more complicated. Frontage didn't matter so much, as in the field it would vary anyway from day to day, and the aim was to teach the cadres of the battalion the principles of the movements and changes of formation.