The 14 crew members from Air France were arrested in Buenos Aires after the daughter of a former member of the Argentine government complained of neglect.
The woman in question alleged that the crew didn't listen when she complained that her neighbour took up too much space, going on to tell airport police on landing that he had also masturbated during the trip, said AFP, citing a source close to the investigation.
The incident, which happened at the end of October 2017, saw the crew taken away by police officers when their plane landed at Ezeiza airport and held for hours at a local police station, only to be transferred to court the next day to be interviewed.
The National Union of Commercial Navigating Personnel (SNPNC) describes "48 hours of anguish" on its website, and denounces an interrogation by an Argentine judge that took place "in conditions flouting fundamental rights".
Air France's management team released a statement saying it was "shocked" and urging French authorities to "shed light on this case".
Air France CEO, Jean-Marc Janaillac, has expressed his indignation at the Ministry of Foreign Affairs.
*How did events unfold?*
In a letter sent to Argentina's ambassador to France, the SNPNC tells the story:
The passenger who made the complaint is aged thirty years, a doctor and the daughter of a former Deputy Minister of Justice in Argentina.
Sitting in economy class, she complained that her neighbour spilled over into her seat several times during the flight while sleeping.
The flight attendants woke the passenger twice but refused to transfer the woman to business class due to lack of space, however, they offered the sleeping passenger another seat.
As soon as she got off the plane, the Argentinian passenger complained at the Buenos Aires International Airport police station, this time accusing the passenger, who was deemed disruptive, of having masturbated during the trip.
The man, a French national, was arrested by police and kept in solitary confinement for 24 hours; he was not given any representation from either a lawyer or the French Embassy.
*Chief flight attendant locked up for hours*
Before going to court, the head of the cabin was locked in a courtroom measuring "one square metre, with no possibility of sitting, drinking or eating, for many hours," according to the SNPNC.
During his hearing, he was questioned by the complainant's father, as a former deputy justice minister.
The Argentine press has so far only published one anonymous judicial source.
"No one has been unduly detained," the source said.
All of the French nationals were eventually released without any explanation and Air France has asked for answers and for an investigation to be opened.