Emissions were estimated to decline 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" and extended a slowdown seen in recent years, Citepa said.

The country unveiled in December its updated pathway for achieving carbon neutrality by 2050. To stay on track, emissions need to fall 4.6 percent every year until 2030.

After France slashed its emissions 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.

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

Cleaning up these sectors poses an enormous challenge for industrialised countries like France, a major economy seen as a leader in transitioning to a low-carbon future.

This 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.

Big, historic polluting nations are under pressure to make faster and deeper cuts to the heat-trapping emissions driving global warming.

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.

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.