I know that Napoleon crowned himself unlike Charlemagne because he didn't want the Pope to have power over him like he did over Charlemagne, but what else? Their conquests look kind of similar but I imagine that's just a coincidence. Was Charlemagne just a propaganda piece or was he more?
Well the bee, which became a piece of Napoleonic heraldry, was based off of little ornamental bees found buried in Charlemagne's tomb.