The 15 crew members of the Legend Airlines charter flight en route from United Arab Emirates to Nicaragua were questioned and released, according to a lawyer for the small Romania-based airline.
She said they are deeply shaken by what happened.
The flight stopped on Thursday at the Vatry Airport in Champagne country for refuelling, and was grounded by French police based on an anonymous tip that it could be carrying victims of human trafficking, the Paris prosecutor's office said.
It said two people have been detained and special investigators are questioning the other passengers.
The unusual and sudden probe disrupted holiday weekend air travel as police cordoned off the airport and all flights in and out of the regional airport were halted, according to the administration for the Marne region.
Some were rerouted.
The airfield is used primarily for charter and cargo flights.
Police sequestered the passengers in the airport, where they have spent two nights on camp beds while the investigation continues, according to the Marne administration.
Investigators from a specialised French crime unit are analysing the case of 300 plane passengers. (AP PHOTO)
It said they initially remained in the A340 plane, surrounded by police on the tarmac, but were then transferred into the main hall of the airport to sleep.
The Indian embassy in France posted on X that embassy staff had obtained consular access to the passengers.
"We are investigating the situation and ensuring the wellbeing of passengers," it said.
Investigators from a specialised French organised crime unit, border police and aviation gendarmes are working on the case.
Legend Airlines lawyer Liliana Bakayoko said the company denies any role in possible human trafficking, and welcomed the news that the plane's crew had been released after questioning as "good news for the airline".
A "partner" company that chartered the plane was responsible for verifying the identity documents of each passenger, and communicated the passengers' passport information to the airline 48 hours before the flight, Bakayoko told the Associated Press.
The customer had chartered multiple flights on Legend Airlines from Dubai to Nicaragua and a few others have already made the journey without incident, she said.
She would not identify the customer, saying only that it is not a European company.
The crew members, who are of multiple nationalities, "are rather traumatised," she said.
"They wrote me messages that they want to see their families for Christmas."
The US government has designated Nicaragua as one of several countries deemed as failing to meet minimum standards for eliminating human trafficking.
