The film Perfume: The Story of a Murderer (2006) is based on the 1985 novel Perfume by Patrick Süskind, and not on a true story.
The novel falls into the 'magical realism' genre as it blends fantastical elements (such as Grenouille's impossibly acute sense of smell) with aspects of the real world (for example, the setting of Paris), and presents the far-fetched or unbelievable as something commonplace. Other novels in the genre include The Picture of Dorian Gray by Oscar Wilde and Nights at the Circus by Angela Carter.
Both the film and novel of Perfume focus on a character who can recognise someone's scent from several miles away, even in an overcrowded city. Grenouille also creates a perfume that has the power to help him escape a death sentence and to turn an angry mob into a mass orgy. Obviously, neither of these examples are possible in reality, so if the novel were indeed based on a true story, this could only have been the case in relation to the more realistic events within the narrative!