What effect do symbols and metaphors have on the understanding of the novel's message in Perfume: The Story of a Murderer?

The central message of Suskind's novel is undoubtedly meant to evoke horror—specifically, that sinister and psychopathic murderers often blend into society, while still exhibiting concerning traits and patterns of behavior. Grenouille's obsession with scent leads to his first murder, and through this act and his subsequent killings, he demonstrates no remorse. Grenouille is emotionally stunted, which can be traced back to the neglect and lack of love he experienced beginning in infancy, his mother having abandoned him at birth.
Another salient theme is the power of perfume and scent to influence emotions. This is exhibited by Baldini's search for the perfect scent, particularly one associated with romance and sensuality. Grenouille is able to escape persecution when the perfume he creates from the women he murders manipulates the public into believing he is innocent. Grenouille's downfall eventually occurs upon releasing a copious amount of this scent in public, causing him to be killed by a mob.
In the novel, perfume symbolizes Grenouille's obsession with the perfect scent and the psychological power of hormones associated with scent. Additionally, perfume is a metaphor for the sins of humanity; perfume allows people to smell good, which masks humankind's evil nature, which is represented metaphorically through the odor of unclean, sweaty skin. Grenouille is repulsed by this unpleasant odor, seeking a cave in order to escape the smell. The cave thus symbolizes his escape from society and safe haven from its unpleasant scent. Grenouille exclusively targets virgin women, symbolizing purity, which translates to the pure and perfect scent he seeks.
Characters themselves can also function as symbols. Grenouille, as a murderer, symbolizes death and psychopathy. Baldini, as his mentor, represents his introduction to the intoxicating realm of perfume. Similarly, settings can also act as symbols. The fish market where Grenouille was born represents the sins of humanity, which is reflected in the location's unpleasant odour and his mother's abandonment. Grasse, the setting in which flowers are grown to make most of the perfume produced in France, is like heaven for Grenouille and associated with his obsession with scent.