BlackRock will provide services for clients in other countries in continental Europe from the Paris office, where it has recently hired senior executives, the source said, partly confirming an earlier report published by the Financial Times.

The move comes less than nine months before Britain's departure from the European Union in March 2019.

"The expansion is part of a strategy to grow in Europe and to move closer to customers and is not related to Brexit," the source said, without saying how many positions would be created.

The world's largest asset manager is also expanding in Germany, Switzerland and Italy, she added.

A charm offensive led by pro-business President Emmanuel Macron - including easing labor rules and tax cuts - might be starting to pay off, with several financial institutions making plans to beef up their Paris operations.

Bank of America is looking to move more jobs than originally envisaged to its new Paris office, one of the biggest such shifts from London ahead of Brexit, sources told Reuters last month.

A Reuters survey in March showed Paris had recently overtaken Frankfurt as the top location for such moves.

BlackRock will drive its expansion in France, Belgium and Luxembourg from its beefed-up office in central Paris. The company has applied to the local regulator to get a license to set up the new investment management business.

The Financial Times said on Monday BlackRock had chosen Paris over London to locate this new business.

Unlike other banks and financial companies, the fund manager has decided not to relocate staff to Paris from London. But its European expansion will take place by expanding in locations outside Britain.

The company had unveiled three top hires in the Paris office last month including Henri Chabadel, a new chief investment officer, and two regional heads of product lines.

(Reporting by Inti Landauro; editing by Michel Rose and Adrian Croft)