Well, the uniform of this unit is green, right?
So I think that it is the unit which was responsible for maintaining order in Paris. It was composed of former soldiers, veterans of 5 campaigns but younger than 40. By 1805, this unit will be used to strengthen the Grande Armée : they were at Dantzig, Friedland, Burgos... This unit was disbanded in 1812, because they were involved in the maret's conspiration.
Regards, EricJ