PARIS (AP) -- France's highest court on Thursday blocked a key part of a contentious farming law that would have brought back a banned pesticide.

The court said that the measure failed to protect the environment and future generations. The rest of the law -- known as the "Duplomb law," after the senator who proposed it -- was allowed to stand.

The bill, passed in early July, aimed to loosen rules for farmers and fast-track projects like water storage. It was backed by the government and major farming unions, but met fierce opposition from scientists, health experts and green groups.

At the heart of the outrage was acetamiprid, a pesticide banned in France since 2018 for its role in harming bees and other pollinators. Farmers, especially sugar beet growers, had pushed for its return.

But the court ruled that the proposal wasn't strict enough, and ignored France's constitutional commitment to environmental protection.

The backlash was swift and widespread. A student-led petition against the law drew more than 2 million signatures -- one of the biggest in French history. Opponents said that the bill was rushed through parliament with barely any debate, and warned that it put public health and biodiversity at risk.

The ruling is a blow to President Emmanuel Macron's government, which had defended the bill until the end.

Critics called the decision a win for democracy and the planet. Some lawmakers have already vowed to push for a full repeal in the coming months.

Acetamiprid is currently approved by the European Union until 2033, and authorized in other member countries.