Total is seeking a 50% stake in a $4 billion project in Iran's giant South Pars gas field, the French energy firm said in a regulatory filing on March 17 detailing talks held with Iranian officials on several projects in 2016.

Total signed a preliminary deal for the South Pars project in 2016, becoming the first Western oil major to sign an energy agreement after the EU and the U.S. eased sanctions as part of a pact to curb Iran's nuclear ambitions.

In a filing to the U.S. Securities and Exchange Commission, Total said the South Pars 11 project would require investment of about $4 billion, with the French firm financing 50.1% with equity contributions and payments in non-U.S. currency.

If finalized, Total would operate the project with a 50.1% stake, China's CNPC would own 30% through one of its subsidiaries and Iran's Petropars would have 19.9%.

Total had not previously given details about the value of the project or indicated the breakdown of ownership.

South Pars is part of a Gulf reservoir that is one of the biggest gas fields in the world, but its development has been hobbled by years of Western sanctions imposed over what the West said was Tehran's bid for nuclear weapons, a charge Iran denies.

The South Pars project is expected to have a production capacity of 370,000 barrels of oil equivalent per day (Mboe/d) and the gas would be fed to the Iranian grid. It would require two offshore platforms and 30 wells.

Total is expected to make a final investment decision by summer, although this would depend on a renewal of U.S. sanctions waivers, Total CEO Patrick Pouyanne said in February. Iran said contracts would be finalized around April.

Total said in its filing that it discussed other projects with Iranian officials in 2016 and carried out technical reviews, including for investment in a 10 million tonne per year LNG plant at Tombak on the Gulf coast.

In February, sources said Total was in talks to buy a stake in the partly-built LNG plant at the port.

The French firm also said in its filing that it discussed plans to invest in the South Azadegan oil field.

Total said it resumed trading with Iran in February 2016, and bought about 50 MMbbl of crude for about $1.9 billion last year, most of it to supply its refineries.

It also purchased 11 MMbbl of petroleum products for $394 million, generating net profit of $2.8 million.

The company also said it was selected alongside other companies to consult on a potential oil and gas pipeline between Iran and Oman.