Frederic Oudea will retain the position of CEO, while Bini Smaghi will become chairman at the bank's annual shareholders' meeting on May 19, Societe Generale said in a statement.

The only big French bank not to have split the two roles until now, Societe Generale was expected to make the separation in line with recent corporate governance recommendations from employers associations AFEP and Medef.

"This change in corporate governance, prepared in 2014, meets the requirements applicable to banks in Europe," the bank said.

"Taking place just after the group successfully joined the European Banking Union, and in an increasingly demanding economic, competitive and regulatory environment, it will allow Societe Generale to continue implementing its strategy and its transformation."

An Italian with a doctorate from the prestigious economics department of the University of Chicago, Bini Smaghi was an executive board member of the European Central bank from June 2005 to December 2011.

He left the central bank well before it became the single supervisor of euro zone banks in November and he has since called for more ECB monetary easing and been critical of budget austerity.

Societe Generale said that GDF Suez Chief Executive Gerard Mestrallet and SNCF executive Barbara Dalibard would also join the bank's board.

Mestrallet heads the Europlace lobby that promotes Paris as a financial centre.

(Reporting by James Regan and Leigh Thomas; Editing by John Irish and Louise Heavens)