Airports staff found the body in a Lufthansa aircraft that arrived in Frankfurt airport form, the Iran capital.
The body was discovered by workers after the passengers of flight LH 601 had left the aircraft and the A340 had been moved to a hangar for maintenance, German newspaper Bild reports.
The same flight scheduled for Friday has been cancelled, according to Lufthansa’s website.
Lufthansa and federal police declined to comment. Frankfurt police was not immediately available for comment.
The incident comes amid widespread unrest in Iran, sparked by the death of Mahsa Amini, a 22-year-old Kurdish Iranian woman who was detained by the Islamic Republic’s morality police for "improper attire" and died in police custody.
Tensions in the country are at boiling point and protests against the death enetered their forty-second day on Friday.
Demonstrators attempted to break into government offices in Mahabad on Thursday after the death of 35-year-old protester Ismaeil Mauludi.
According to human rights group Hengaw, at least 3 citizens — identified as Keyvan Darvishi, Mohammad Lotfolahi, and Mohammad Shariati — were killed.
The UN human rights office on Friday voiced concern about Iran’s treatment of detained protesters and said that authorities were refusing to release some of the bodies of those killed.
“We’ve seen a lot of ill treatment...but also harassment of the families of protesters,” Ravina Shamdasani, spokesperson of the Office of the High Commissioner for Human Rights, told a Geneva press briefing, citing multiple sources.
She added that in some cases, authorities were withholding the bodies of dead protesters from families or only releasing them on condition that they do not hold a funeral or speak to the media.