PARIS — A French court on Monday dismissed a landmark case against the U.S. makers of Agent Orange, disappointing victims who had seen the trial as a potential path toward accountability and compensation.

The case was initiated by Tran To Nga, a 79-year-old French-Vietnamese woman, who says she was one of millions of people who were exposed to the toxic herbicide by the U.S. military during the Vietnam War. Tran said she will appeal the ruling.

Hundreds of thousands of U.S. veterans have received disability benefits because of illnesses that in medical research have been linked to Agent Orange. Compensation for Vietnamese civilians, however, has lagged.

If the court in the Parisian suburb of Évry had sided with Tran, a former journalist, she would have been the first Vietnamese civilian to successfully sue the companies that produced Agent Orange.

But the court argued that it does not have jurisdiction, largely because the accusations are linked to wartime actions by the U.S. government, according to Agence France-Presse. This had been a key argument of the implicated companies, including American multinational Dow.

In a statement on Monday, German company Bayer — which acquired Agent Orange producer Monsanto — said it is "well-established" 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 product during wartime."

Tran's lawyers said the court decision is based on an "obsolete definition of the principle of immunity from jurisdiction."

They argued that the companies that supplied Agent Orange to the U.S. government were aware of the herbicide’s toxicity and acted without coercion. Tran’s lawyers on Monday also called for full access to the communications between the U.S. government and the companies at the time.

The U.S. military deployed or tested Agent Orange and similar chemicals in Vietnam, Cambodia, Thailand, the Korean demilitarized zone and Laos between the early 1960s and 1971. The primary aim in conflict zones was to destroy crops and to defoliate forests used by enemy fighters.

But the substances also entered the food chain, and parents passed the toxins on to their children, according to researchers. Tran said she was hit by the chemicals when they were dropped from a U.S. plane.

She developed numerous conditions that have been linked to Agent Orange, including Type 2 diabetes. After Tran’s exposure to the herbicide, one of her daughters died of a heart defect, while her two surviving daughters were diagnosed with skin and blood conditions.

The case was tried in France because Tran became a French citizen after moving here in the early 1990s. French nationals can sue foreign entities even if the crime was committed abroad.

In their statement on Monday, Tran’s lawyers said they hope she “will have sufficient strength, given the conditions she suffers from, to be able to carry out her fight until the end.”