Factual error: The hanging is shown using the "standard drop", with a trapdoor, breaking the neck. This was not introduced until the 19th century (after France had abandoned the gallows for the guillotine), whereas the film is set in the 18th century. In those days the victim was just strung up on the gallows and left to strangulate (the "short drop").
Factual error: Putrescine and cadaverine are the smells of decay that set in frighteningly fast as soon as something or someone is dead. An average human nose has evolved to pick up on the very distinctive, revolting smell of death, even in the tiniest amount. Jean Baptiste is attracted to the smell of women at their "ripest" hormonally, and tries to capture their pheromones. But really, they'd only smell like death.
