The Madagascan president's chief-of-staff has been charged in the UK with seeking a bribe from a gem mining firm.
Romy Andrianarisoa and an associate are accused of offering the British firm Gemfields licences in Madagascar in return for around £225,000.
She and her associate, Philippe Tabuteau, have been charged with requesting, agreeing to receive or accepting a bribe.
Both were remanded in custody after a brief court appearance on Saturday,
Ms Andrianarisoa, 46, and French national Mr Tabuteau, 54, are also accused of trying to land a 5% equity stake in any Gemfields Madagascar projects, according to the National Crime Agency (NCA).
The agency said that the pair were arrested in the Victoria area of central London on Thursday afternoon, at a meeting where they were suspected of having attempted to solicit a bribe.
Andy Kelly, the NCA's head of international corruption, said: "I am grateful to Gemfields for bringing this matter to our attention and for their ongoing co-operation with the investigation."
Ms Andrianarisoa and Mr Tabuteau appeared in court on Saturday and have both been remanded in custody to next appear at Southwark Crown Court on 8 September.
The NCA did not specify what licences the alleged offences related to.