France becomes the third EU nation after Belgium and Portugal to maximise its reserves, well ahead of a government deadline set for November.

Across the EU, gas reserves stand at an average level of 89 percent.

Countries have spent the months since Russia’s February 24 attack on Ukraine scrambling for alternative sources of fuel, including imports of liquid natural gas (LNG).

“The campaign to refill gas storage for winter 2022-23 is complete, with storage more than 99 percent full,” the Energy Regulation Commission (CRE) said in a statement.

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With 130 terawatt-hours (TWh) of gas in stock, higher than the average seen in recent years, France’s supply amounts to around two-thirds of winter consumption by small- to medium-sized businesses and households, the CRE said.

But the body also urged a “massive collective effort to reduce our energy consumption” as supplies could still run tight depending on the winter weather, saying companies, government, local authorities and members of the public must all contribute.

“To prepare for possible tense situations in the coming months, reasonable use of the reserves as well as an effort to limit consumption… seem necessary beginning immediately,” gas storage firms Storengy and Terega agreed in a joint statement.

Most of France’s gas reserves are stored in natural underground spaces such as aquifers dotted around the country.

Russia cut off deliveries of natural gas to France — which has strongly backed sanctions and military aid to Ukraine over Moscow’s invasion of its neighbour – from September 1.

Paris is expected on Thursday to present its “energy sobriety plan” aimed at slashing consumption by 10 percent in two years.

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Looking to the coming months, Storengy and Terega said that the country’s gas supply could remain “balanced overall” in an “average winter” – although there was “little room for manoeuvre”.

But a severe or lasting cold snap could leave supply short of demand by around five percent, forcing measures to cut usage.