PARIS, April 14 (Reuters) - BNP Paribas has signed an agreement with China's Fosun Group to acquire its 9% stake in Belgian insurer Ageas for a sum the French bank estimates at 730 million euros ($776.87 million).

Ageas and BNP Paribas are long time partners via a joint shareholding in AG Insurance, Belgium's leading insurer. Ageas owns 75% and BNP the remaining 25%.

"Ageas is pleased to see that BNP Paribas recognises, through this investment, the value of its partnership for the long term and the potential of the company going forward," the Belgian insurer said in a separate statement.

Last month Ageas dropped plans to buy Direct Line after the British home and motor insurer turned down a revised 3.17 billion pound ($3.95 billion) takeover bid from the Belgian insurer. ($1 = 0.9397 euros) ($1 = 0.8032 pounds) (Reporting by Benoit Van Overstraeten Editing by David Goodman)