France’s constitutional court on Thursday rejected the reintroduction of a controversial insecticide in a significant blow to the government and major farming lobbies that had supported its return.

The court’s judges ruled that allowing the use of acetamiprid, an insecticide currently banned in France, would violate the “Charter of the Environment,” a French constitutional text.

Acetamiprid’s proposed reintroduction was part of a new French law aiming to make life easier for farmers by allowing the use of some pesticides as well as by cutting red tape and easing permit approval for new breeding and water storage facilities.

The judges stressed that neonicotinoids — a class of insecticide that includes acetamiprid and that works by obstructing the nervous systems of insects — can be allowed in exceptional situations but only for a limited time and for well-defined crops. These conditions were not respected in the text of the law, the judges found.

The law, which was dubbed “Loi Duplomb” after the conservative senator who introduced it, was a response to the massive farmer protests of 2024. It had already been approved in the parliament.

The law is backed by the government and by major farming lobbies but is strongly opposed by left-wing parties, which have flagged its negative impact on biodiversity.

More than 2 million French citizens signed a petition launched last month by a 23-year-old student to repeal the law, putting additional pressure on the government.

The law polarized French public opinion between the country’s powerful farming lobbies and its more ecologically minded citizens worried about the harm done by pesticides to pollinators and human health. Its opponents urged French President Emmanuel Macron not to sign the law into effect.

Macron’s office said Thursday that the president had “taken note” of the ruling and will enact the Duplomb law “as soon as possible” in its modified version per the constitutional court’s ruling. Acetamiprid, in other words, will remain banned.

Left-wing opposition figures celebrated the news, with the agriculture ministry expected to comment on the decision later Thursday evening.

Farming lobby FNSEA, however, slammed the ruling. “This decision marks the pure and simple abandonment of certain sectors of French agriculture, at a time when our dependence on imports is increasing to the detriment of our social and environmental requirements,” FNSEA President Arnaud Rousseau wrote in a social media post.