Le Sac de charbon is both reminiscent of Molière's farces with their many tricks and Les Fourberies de Scapin because of the presence of a bag that serves as a hiding place for a character. However, the fun of traditional farce scenes is linked here to a series of violent deaths caused by Pierrot, the play's protagonist. Initially stealing out of necessity, Pierrot then lashes out at the rich and contemptuous Niflanguille, and in the end becomes a fearsome assassin, even more uncontrollable than Polichinelle. However, in the end, Christian morality is saved, justice is effective and order is restored, since the murderer ends up being hanged and the evil rich man punished.
Duranty's Pierrot is as ferocious and devious as the Pierrot of Deburau's realistic pantomimes that had contributed to the glory of the Théâtre des Funambules a few decades earlier.

The rich Niflanguille goes to buy a bag of coal. He comes across the hungry Pierrot, who asks for his help in vain. The coalman cheats Niflanguille out of the weight of the bag. Pierrot hides in the bag and beats up the coalman, Niflanguille and the servant. Back home, Niflanguille looks for a sword to pierce the recalcitrant bag, but Pierrot gets it out in time and forces the servant to take his place. While Niflanguille pierces the bag and his servant with it, Pierrot runs away with a bag of money. A Gendarme wants to hang Niflanguille for murder, Pierrot for theft and the coalman for swindling. Pierrot kills the Gendarme and puts him in the sack, which he throws away, while Niflanguille flees through the window. Pierrot kills the coalman to avoid sharing the money, then orders wine which he pays for by beating the innkeeper with a stick. The Commissaire arrives with Niflanguille; he hangs Pierrot, but confiscates the money to punish the bad rich man.