ÉVRY, France — Almost six decades after the U.S. military began dropping a toxic herbicide known as Agent Orange in the Vietnam War, a French courtroom in a Parisian suburb has become the unlikely setting for a faceoff between a woman who says she was a victim and some of the world's largest chemical and pharmaceutical corporations that supplied the substance.

The landmark case has pitched Tran To Nga, a 79-year-old, against 14 companies. A ruling is expected on Monday.

If the court in Évry sides with the companies, including American multinational Dow, it would crush hopes for what activists have seen as a “historic trial” and a unique chance for accountability. But if the court rules in Tran’s favor, she would be the first Vietnamese civilian to win such a case.

“What I want from the companies that produced Agent Orange is that they have the courage to recognize their crimes and the courage to fix what they caused,” Tran said in an interview, sitting between two desks in her small living room.

On the tidy desk to her right, carefully filed documents and correspondences testified to more than half a decade of legal proceedings.

The desk to her left was strewn with boxes of pills and various medications.

Tran has numerous conditions that in medical research have been linked to the long-term effects of Agent Orange, including Type 2 diabetes and cancers. Among her three daughters born after her exposure to Agent Orange, one died shortly after birth due to a heart defect and the surviving two have been diagnosed with blood and skin conditions.

Tran and her lawyers say the only explanation for those conditions is her exposure, when she was directly hit by chemicals dropped from an American plane. Tran says at the time she was a journalist aligned with the communist Viet Cong forces, one of the U.S. military’s key foes in the region during the war. She was later imprisoned by the U.S.-aligned South Vietnamese government.

The companies have cast doubt on her recollection of events and question whether her conditions are linked to Agent Orange.

“While we have great sympathy for Ms. Tran to Nga and all those who suffered during the Vietnam War, we believe the court should dismiss the claims,” German multinational Bayer said in a statement on Friday.

Agent Orange and similar chemicals were used by the U.S. military between the early 1960s and 1971 to destroy crops deemed crucial for the enemy side’s food supplies and to defoliate forests used as hiding spots in Vietnam, Cambodia, Thailand, the Korean demilitarized zone and Laos.

After American planes dropped the herbicides, lush trees would turn into wooden skeletons. The toxins also entered the food chain and through that route reached millions of people.

In the United States, doctors began to notice unusual patterns of cancers and diabetes among returning soldiers, along with birth defects and other medical problems in their children.

Agent Orange contained TCDD, the world’s most toxic dioxin, which has since been linked to at least 17 illnesses and cancers. Its components continue to pollute areas where they were dropped, and they may linger for decades to come.

In Vietnam, up to 4.8 million civilians may have been exposed, according to some estimates. Many victims passed the dioxins onto their sons or daughters, and the number of babies born with abnormalities multiplied after the war.

Initially unbeknown to many U.S. soldiers, American military bases had been among the most contaminated places. The 1991 Agent Orange Act paved the way for hundreds of thousands of U.S. veterans to qualify for Veterans Affairs disability benefits in the following years.

But support for victims elsewhere has lagged. In 2005, a New York district court dismissed a civil lawsuit brought forward by Vietnamese victims against several U.S. companies that produced the herbicides.

“In any of the cases that have gone to American court, the chemical companies have always been protected under the same immunity that the U.S. government has,” said Susan Hammond, executive director of the War Legacies Project, which tracks the long-term effects of war in Vietnam, Laos and Cambodia.

The French case could produce a different result.

The case is being tried here because Tran became a French citizen after moving to the country in the early 1990s to run a travel agency. Under French law, citizens can sue foreign entities or individuals even if the crime was committed outside the country.

The ruling won’t have much effect on the U.S.-focused companies that are among the parties to the suit. But Dow is active around the world and would have an interest in complying with a European court ruling. The ruling is also significant for Germany’s Bayer, which is implicated because it acquired the accused U.S. corporation Monsanto.

Tran’s lawyers have asked for about $360,000 in compensation and provisional damages, but she said the financial claims are secondary.

“I’m not fighting for myself; I’m also fighting for justice for my Vietnamese compatriots and for Agent Orange victims in the United States and other countries,” she said

A ruling in Tran’s favor “would be a very symbolic win,” Hammond said. “A lot of what people impacted by Agent Orange are looking for is acknowledgment and recognition that they've been harmed by these chemical companies.”

NGOs allege that the chemical corporations that supplied Agent Orange knew about the risks but did not halt its use or reduce the toxicity. Tran’s case is largely built on personal testimony and documents that emerged in prior legal challenges.

“We managed to collect enough information to demonstrate that the companies had at the time a perfect knowledge of the exceptional toxicity of Agent Orange, and that despite that, they continued to produce it in the same way,” said Amélie Lefebvre, one of Tran’s lawyers at the Parisian Bourdon & Associates law firm, which is working pro bono.

“We have the elements to demonstrate that they had the choice, and if we succeed in convincing the tribunal, this specific reasoning could be used elsewhere,” she said.

The companies have rejected any responsibility.

“It has been well-established by courts for many years that wartime contractors operating at the behest of the U.S. government are not responsible for the alleged damage claims associated with the government’s use of such products during wartime,” Germany’s Bayer said in its statement on Friday.

Dow did not respond to a request for comment. On its website, it states that “decades of study relating to Agent Orange have not established a causal link to any diseases, birth defects or other transgenerational effects,” adding that the matter should be up to “the governments of the United States and Vietnam” to resolve.

The U.S. Department of Veterans Affairs, however, has acknowledged that “veterans who were exposed to Agent Orange may have certain related illnesses.”

Tran said she has spent much of her adult life trying to forgive. She was awarded France’s Legion of Honor for her societal activism in Vietnam and France.

But she said she has struggled to come to terms with the arguments the companies use to defend themselves.

“They lied,” she said about the companies’ lawyers, adding that some of them are “too young to know the cruelty of war.”