Thales, Europe's largest defence electronics group whose largest shareholder is the French state, announced the deal in December last year. Companies are seeking to boost their presence the booming security services market, which includes encryption and biometric passports.

Last month, it offered to sell its nShield GP HSM (general purpose hardware security modules) to address the European Commission's concerns about the deal. Such technology generates keys and encrypt and decrypt data.

The EU competition enforcer subsequently sought feedback from rivals and customers.

"The scope of the divestiture has been confirmed as being Thales GP HSM," Thales spokeswoman Victoire Chartier said, declining to comment on the EU ruling.

The Commission also declined to comment. It has set a Jan. 8 deadline for its decision.

Franco-Dutch Gemalto's second-biggest shareholder is state-owned bank Bpifrance.

(Reporting by Foo Yun Chee; Editing by Mark Potter)

By Foo Yun Chee