Russian gas giant Gazprom, Italian gas company Eni, and France's Electricite de France (EdF) signed a memorandum of understanding, bringing the French company into the South Stream gas pipeline, RIA Novosti reported.
The document was signed on Saturday at the International Economic Forum in St. Petersburg in the presence of Russian President Dmitry Medvedev and French President Nicolas Sarkozy.
The Russian and Italian companies will each give Edf 10% of their shares, or 20% of the South Stream gas pipeline project.
South Stream, with an estimated price tag of 25 million euros, will connect Russia and the EU across the Black Sea and the Balkans, bypassing Ukraine.
Gazprom said last week it was ready to start South Stream's construction in 2013 and should begin pumping gas to Europe by 2015.