PARIS — Even from his seaside holiday retreat at the Fort de Brégançon, President Emmanuel Macron will be closely watching a key court ruling on a controversial pesticide on Thursday.

The question of whether French farmers will be allowed to protect their crops with a chemical called acetamiprid is far from being an obscure technical matter. In fact, it lays bare a major fault line in French politics between the powerful agricultural sector and more ecologically minded citizens worried about pesticides harming pollinators and human health.

Macron’s challenge is that he is being squeezed politically between green-minded voters — often concentrated in metropolitan areas — and influential farmers from rural heartlands, while his liberal centrists falter and Marine Le Pen’s far-right National Rally eyes the presidency in 2027.

France’s top constitutional court is set to decide Thursday whether a bill that includes the reauthorization of acetamiprid — under scrutiny for its effects on the nervous systems of both bees and humans — is constitutionally sound.

This is a routine review for every piece of legislation, but it is drawing unusual attention in this case after an online petition calling for the law’s repeal went viral.

As of Tuesday, more than 2 million French citizens had signed a petition launched by a 23-year-old student in Bordeaux, Eléonore Pattery, calling for the “immediate repeal” of the so-called Loi Duplomb, named after the conservative senator who introduced the legislation. The petition, hosted on a government portal, can spur parliamentary debate but doesn’t bind lawmakers to act.

The debate around acetamiprid has put France — and Macron — in a bind.

In 2018, the European Union banned three neonicotinoids, a group of insecticides that includes acetamiprid, over the threat they pose to pollinators such as bees. It did not, however, ban acetamiprid itself, which is considered less toxic to bees and breaks down faster in soil.

Paris, seeking environmental leadership of the EU, went further than its neighbors and banned acetamiprid anyway.

Then the political calculus changed. Like many other countries in Europe, France has faced surging dissent from farmers across the country. They decry what they see as excessive taxation and regulation, and argue that bans like the one on acetamiprid left them at a competitive disadvantage.

With a European election looming last year, the French government sought to appear sympathetic to the farmers’ cause. “The goal of reducing pesticide use should not leave our farmers helpless and without solutions. In the end, no one would benefit — not the environment, not health and not agriculture,” then-Prime Minister Gabriel Attal, now head of Macron’s Renaissance party, said at the time.

The Loi Duplomb reflects that shift toward siding with farmers’ demands. The bill aims to ease their burden not only by reintroducing acetamiprid but also by loosening rules on the construction and expansion of large livestock buildings. It is backed by the government and by major French farming lobbies FNSEA and Jeunes Agriculteurs, who played an important role in shaping the legislation.

During the protests, farmers were widely expected to receive public support — they are often viewed as crucial to France’s core interests and one of the last holdouts of rural life in an urbanized country.

Popular backlash

This time, however, public opinion appears to have shifted.

The historic success of the petition against the Loi Duplomb was fueled by high-profile opposition from celebrities, movie stars and influencers. Signatories must log in through a secure government platform used for taxes or health services, ensuring each person signs only once. A poll released last month by French polling institute Cluster17 showed 61 percent of respondents opposed the bill — 41 percent strongly. Just 33 percent said they were either “somewhat in favor” or “strongly in favor.”

The science behind acetamiprid’s toxicity is contested. In 2024, the European Food Safety Authority proposed drastically lowering recommended daily intake doses, citing “major uncertainties” about the substance’s effect on the nervous system’s development — while stopping short of calling for a ban.

France’s National Order of Physicians has come out against the Loi Duplomb, writing in a statement that “doubt is not reasonable when it comes to substances that may expose the population to major risks: neurodevelopmental disorders, pediatric cancers, chronic diseases.”

Some lab and animal studies suggest acetamiprid may cause DNA damage or act as a hormone disruptor — both potential cancer pathways — but the U.S. Environmental Protection Agency has concluded it’s “not likely to be carcinogenic to humans.”

Macron has delayed responding to the viral petition until after the Constitutional Council issues its ruling.

Two constitutional challenges were filed against the law — one citing environmental rights, the other criticizing the fast-tracked process used to bypass a debate in the National Assembly.

If the court green-lights the Loi Duplomb, Macron will be left with few options. Because the petition passed the 500,000-signature threshold, it may trigger a parliamentary debate — though there’s no obligation to hold a new vote, since the law has already passed.

Macron could also choose not to enact the bill — an extremely rare move that could open him up to accusations of defying the legislature’s authority.

Whatever happens, the controversy is likely to continue dogging the French president. Even within his own ranks, divisions are clear: During the final vote last month, 26 of the 176 MPs in the three-party coalition backing Macron voted against the bill, while 15 abstained.