Areva, based in Paris, would also need to sell new shares to extend its uranium mining business and ride the global revival in nuclear energy, he said.
The stake sale would be part of a broad shake-up of the French nuclear industry. President Nicolas Sarkozy has asked the finance ministry to review all possible options for Areva, including selling shares to the public or merging it with the power stations maker Alstom.
The state directly or indirectly owns 93.4 per cent of Areva, of which CEA holds the bulk.
The final decision on the stake sale will come from the government. The state would want to keep a golden share, or an equivalent controlling mechanism, in units that were of strategic importance to France, Bugat said.
These include Areva's nuclear submarines units and the whole nuclear fuel supply chain, from uranium mining to fuel recycling, he said.
Companies like Areva and Westinghouse Electric of the United States, now owned by Toshiba of Japan, are vying for a bigger piece of a market that is expanding as countries from Britain to China plan to build more nuclear reactors to reduce reliance on crude oil and gas.