The film is a 1930s-set drama to be directed by French helmer Rebecca Zlotowski, reported Variety online.
"Planetarium" will mark Portman's first time working with a French director since her role in Luc Besson's "Leon" in 1994.
The 33-year-old actress has been beefing up on her French to prepare for the role.
Although plot details are kept under wraps, Zlotowski said
the film follows the journey of sisters who are believed to possess the supernatural ability to connect with ghosts.
They cross paths with a visionary French producer while performing in Paris.