Gabon’s former prime minister Alain-Claude Bilie-By-Nze, now one of the country’s most prominent opposition leaders, has been placed in pre-trial detention as part of a criminal investigation that his party denounces as a politically driven attempt to sideline a key rival.

Prosecutors say Bilie-By-Nze is being investigated for alleged fraud and breach of trust linked to the organisation of a national cultural festival held in 2008, when he was a rising figure within the regime of then-president Ali Bongo Ondimba. According to the public prosecutor, a service provider involved in the event claims it was never paid for its work and has filed a complaint naming the former premier.

Investigators are focusing on the alleged non-repayment of five million CFA francs, roughly 9,000 dollars, which Bilie-By-Nze is said to have received in connection with the festival. Authorities have not detailed how the money was supposedly misused, nor have they indicated whether other officials from the period are under scrutiny.

His Ensemble pour le Gabon party has reacted sharply, insisting the dispute concerns a debt owed by the Gabonese state and accusing the judiciary of unfairly “imputing it personally” to Bilie-By-Nze even though, they argue, he acted within an official institutional framework. The party condemned his arrest as “arbitrary, brutal, and manifestly contrary to the fundamental principles of the rule of law”.

Bilie-By-Nze served as the last prime minister under Ali Bongo, who was toppled in a military coup led by General Brice Oligui Nguema in 2023. In the political realignment that followed, the former premier broke decisively with the old regime and rebranded himself as a leading opposition voice, criticising both the Bongo era and the new military-led authorities.

He went on to become a central challenger to Nguema, finishing as runner-up in the most recent election and positioning himself as a focal point for those demanding a rapid return to civilian rule and deeper political reforms.

His detention now raises the stakes in Gabon’s fraught transition. Supporters see the case as a warning to other dissenters, while authorities insist they are simply pursuing a long-standing financial dispute through the courts. For many Gabonese, the affair has become a test of whether the post-coup leadership intends to break with past practices or replicate them under a new guise.