It now owns all the shares in the lender after paying the money to fellow European bank Dexia for its 20 per cent stake in the company.
Around $952 million is to be spent on buying the Dexia stake, while a further $46 million will go on the purchase of Credit du Nord's Etoile Gestion asset-management unit.
"For Societe Generale, this transaction will contribute to strengthen its positioning in retail banking in France, a profitable market which has demonstrated its resilience," the bank said.
The deal is to be financed with the some of the proceeds from a recent $7 billion sale of stock.
Last month, Societe Generale warned its clients that it is still not certain that the world has escaped "global economic collapse".
In its exploration of the potential dangers of the future, the bank said that high public debt is unsustainable in light of an ageing population.
By Gary Cooper