The star, who recently moved to Paris with her French boyfriend, is suing for €50,000 ($70,000) in damages from the author and his publisher JC Lattes over the best-selling 'La premiere chose qu'on regarde' (The first thing we look at).
The book's heroine, Janine Foucamprez, is described as strongly resembling Johansson, who is due to attend the Cannes film festival this week.
The first part of the novel is told through the eyes of a garage mechanic who "resembles a better version of Ryan Gosling" and thinks Johannson has turned up on his doorstep.
The actress alleges the writer and publisher used her image and fame to publicize the novel, which has sold 100,000 copies since it was published in March 2013, and is seeking an injunction to stop it being translated or adapted for cinema.
The novel features amorous relationships that "never existed", said prosecutor Vincent Toledano. "It does what the tabloids do, it says anything."
"Creative freedom" does not mean the author can use Johansson's intellectual property rights without authorization, he added.
But Anne Veil, for the defence, said no invasion of privacy had been committed, arguing that the book evoked mere "fads" and "flirts" but no relationships.
If Delacourt knew that Johansson would have "kicked up such a racket, he would have chosen someone else," she added.
The tribunal is due to hand down its judgement on July 2nd.
In January Johansson hit the headlines when she gave an interview in which she talked about experiencing Parisian rudeness since moving to the city to be with her boyfriend, French journalist Romain Dauriac.
Speaking in an interview on The Late Show with David Letterman, Johansson said that “the stardust twinkles” had started to wear off since she moved to the capital.
The star, famous for her roles in the films 'Girl with the pearl earring' and 'Lost in Translation', recently moved to Paris to be with her French journalist fiancé Romain Dauriac, who is the former editor of the French urban art magazine Clark.
While she describes the city as “great”, she did have a few complaints to share about the behaviour of Parisian residents.
“I was like, 'People aren't rude, they're wonderful!' That was before I was a mainstay there and then people decided that once I wasn't going away, they could just be rude to me!"