Franco-Gabonese Sylvia Bongo Ondimba Valentin, ex-wife of ousted president Ali Bongo, was charged on 28 September with money laundering, forgery and falsification of records.
According to Gabonese media reports, the 60-year-old was taken into custody at a prison in the capital Libreville following a long hearing in front a judge and imprisoned late on Wednesday, her Paris-based lawyer Francois Zimeray said.
Sylvia Bongo had been under house arrest in Libreville since the 30 August coup brought the curtain down on 55 years of rule by the Bongo dynasty.
Ali Bongo, 64, who had ruled the central African country since 2009, was overthrown by military leaders moments after being proclaimed the winner in a presidential election.
The election result was branded a fraud by the opposition and the military coup leaders, who have also accused his regime of widespread corruption and bad governance.
The putschists accuse Sylvia Bongo of having manipulated the former president, who is suffering the after-effects of a serious stroke in 2018.
They say she and one of the couple’s sons have effectively pulled the strings in the oil-rich country for the past five years and have misused public money.
Sylvia Bongo had been isolated from her husband, and her French lawyers had complained of what they said “appears to be a hostage-taking”.
“We condemned this illegal procedure,” lawyer Zimeray said on Thursday following her jailing.
“There is a difference between justice and arbitrary actions, between the law and revenge.”
Their eldest son, Noureddin Bongo Valentin, has been charged with corruption and embezzling public funds with several former cabinet members and two ex-ministers.