The slowdown comes as appetite for climate action flags and major economies in Europe and elsewhere struggle to make good on their pledges to reduce planet-warming pollution.

France's emissions were estimated to have declined 1.6 percent year-on-year, said Citepa, a non-profit organisation tasked by France's ecology ministry with tallying the country's greenhouse gas inventory.

The reduction of 5.8 million tonnes of CO2 equivalent was "far below the pace needed to reach 2030 targets" which would require cuts nearly three times larger, Citepa said.

"The decrease in emissions is confirmed for 2025. This is an encouraging sign, but it is not enough. We must collectively remobilise with all emitting sectors," Monique Barbut, France's Minister for Ecological Transition, said in a press release.

France, often seen as a leader in transitioning to a low-carbon future, unveiled in December its updated pathway for achieving carbon neutrality by 2050.

To stay on track, greenhouse gas emissions need to fall 4.6 percent on average every year until 2030.

After France slashed its output by 3.9 percent in 2022 and 6.8 percent in 2023, the rate slowed sharply to 1.8 percent in 2024.

Citepa had earlier predicted a decline of just 0.8 percent in 2025 but said fresh data and updated methods of calculation had allowed a "more accurate" estimate for the full year.

- Climate risk -

Big polluting nations most responsible for climate change are under pressure to make faster and deeper cuts to the emissions driving record-breaking global temperatures and more extreme weather events.

Scientists say the last three years have been the hottest globally on record.

The result in France echoes a slowdown in neighbouring Germany, where emissions fell just 1.5 percent in 2025, the Agora Energiewende expert group said in its annual report last week.

France encouraged energy conservation after Russia's invasion of Ukraine in 2022 but since then has faltered in decarbonising some of its most polluting industries.

While improvements were recorded in 2025 in heavy-emitting sectors such as industry, agriculture and transport, they remained virtually flat in energy and waste treatment, Citepa said.

The latest assessment highlighted the urgency for France to phase out its use of fossil fuels, said Anne Bringault, a director at Climate Action Network France.

"It is high time to take seriously the climate risk but also the geopolitical risk of making us suffer from our dependence on fossil fuels, which are overwhelmingly imported," she told AFP.

The European Union has pledged to cut its net greenhouse gas emissions by 90 percent by 2040 compared to 1990 levels. It had already achieved a 37 percent reduction by 2023.