Roman Polanski is suing the Academy of Motion Picture Arts and Sciences after being kicked out of the organisation.
The Pianist director was expelled from the Oscars body along with Bill Cosby in May last year.
A lawyer for the fugitive filmmaker said he was expelled “without warning” and with no chance to respond.
The Academy later said in a statement its removal of the Oscar winner was “fair” and it will not reverse the decision.
The statement read: “The procedures taken to expel Mr Polanski were fair and reasonable. The Academy stands behind its decision as appropriate.”
Polanski admitted unlawful sex with a 13-year-old girl in 1977, later fleeing the US after fearing a plea deal would be scrapped.
Polanski’s Oscar nominations since his 1977 guilty plea
- 1981: Best Director for Tess
- 2003: Best Picture for The Pianist
- 2003: Best Director for The Pianist (winner)
Polanski’s lawyer, Harland Braun, filed the case at the Los Angeles Superior Court last week.
The move comes after Polanski threatened to sue last year.
At the time of the expulsion, the Academy said its board “has voted to expel actor Bill Cosby and director Roman Polanski from its membership in accordance with the organisation’s Standards of Conduct”.
“The Board continues to encourage ethical standards that require members to uphold the Academy’s values of respect for human dignity,” it added.
At the time, BBC reporter James Cook asked: “Why did it take Hollywood more than 40 years to decide that the statutory rape of a 13-year-old was beneath its precious “values of respect for human dignity?
“The real answer does not lie in bureaucracy but in shame. The industry has been shamed into action by the disinfecting sunlight of the #MeToo and Time’s Up movements.”
Mr Braun has also written to the Oscars board on behalf of Polanski.
Documents say the legal action is to “redress the Academy’s improper administrative action” to “summarily expel” Polanski.
Mr Braun told the Press Association: “If you notice, we are litigating the fairness of their procedure.
“They threw him out without warning and without giving him a chance to respond.
“There was not even any notice of why, after 40 years, on the same day as Cosby.
“Give me a break.”
Mr Braun claims in the writ that: “The Academy failed to comply with its own rules, polices, and regulations” when it ejected Polanski.
What did Polanski do?
The unlawful sex case against Polanski, now aged 85, has dragged on for more than 40 years.
Polanski admitted unlawful sex with Samantha Geimer, who was a minor in 1977, and served 42 days in prison, but later fled the US over concern a plea bargain deal would be scrapped.
He has French and Polish citizenship, and has evaded various extradition attempts by US authorities.
France – where he lives – does not extradite its own citizens. A Polish court also rejected a US request when he was filming in Krakow in 2015.
The Swiss authorities also turned down a US warrant in 2010, after placing Polanski under house arrest for nine months.
In 2017, he was picked to head the jury at the Césars, the French equivalent of the Oscars but stepped down after the move sparked outrage.
Ms Geimer told a US court in 2017 she had forgiven Polanski and wanted to move on.
Follow us on Facebook, on Twitter @BBCNewsEnts, or on Instagram at bbcnewsents. If you have a story suggestion email firstname.lastname@example.org.