Ms Adelkhah was arrested in June 2019 and convicted on national security charges that her supporters denounced as absurd.
Although she was released from prison in February, she remained unable to leave Iran.
A well-known researcher in Iranian Shiite religion and politics, Ms Adelkhah landed back in Paris on Tuesday, her employer Sciences Po University said. They had set up a support group to secure her release.
“After so many years of being deprived of her freedom, what an emotion to finally welcome home our colleague Fariba, a symbol of our battle for academic freedom,” said university director Mathias Vicherat.
Ms Adelkhah was one of some two dozen foreign nationals held by Tehran in what activists and western governments have described as a deliberate strategy of hostage-taking aimed at extracting concessions from the West.
France's Eiffel Tower lit up to support Iran's activists – in pictures
Several foreign prisoners in Iran have been released in recent months, including five Americans freed in a complex exchange for billions of dollars in Iranian funds that had been frozen in a South Korean account.
In May, Iran freed French prisoners Benjamin Briere and Bernard Phelan, the latter also an Irish national, after their health deteriorated during hunger strikes.
But about a dozen foreigners remain held by Iran including four French citizens: teacher Cecile Kohler and her partner Jacques Paris, Louis Arnaud, described by his family as an innocent traveller, and a man identified only as Olivier.
In a call with Iranian President Ebrahim Raisi at the weekend to discuss the current conflict between Hamas and Israel, French President Emmanuel Macron “reiterated his deep concern” over the detainees and requested their immediate release.
“I think of my former fellow women prisoners at Evin (prison in Tehran) and my French compatriots, Cecile, Jacques, Louis and Olivier, who have not yet regained their freedom,” Ma Adelkhah said in a statement released through her supporters.
She was arrested in June 2019 along with her French colleague and partner Roland Marchal.
Mr Marchal was released in March 2020 in an apparent prisoner swap after France released Iranian engineer Jallal Rohollahnejad, who faced extradition to the US over accusations he had violated sanctions against Iran.
Ms Adelkhah was sentenced in May 2020 to five years in prison for conspiring against national security.
She was allowed home in Tehran in October 2020 with an electronic bracelet but was then returned to jail in January 2022.