Former prime minister Lionel Zinsou, who lives in France, was found guilty of using false documents and "exceeding" spending limits in his 2016 bid for the West African nation's presidency.

The judgement is the latest in a string of legal setbacks for rivals of President Patrice Talon, whom critics accuse of cracking down on opponents.

Multi-millionaire Sebastien Ajavon, who has repeated voiced his ambitions for the top job, was sentenced in absentia to 20 years for drug trafficking in October.

Former president Thomas Boni Yayi left Benin in June, ostensibly for medical treatment, after being kept under de-facto house arrest after he criticised one-sided parliamentary elections that sparked bloody street protests.

Talon, a business magnate who made his fortune in cotton, came to power in 2016 vowing to stamp out corruption and mismanagement in a country that has a reputation as one of the region's most stable democracies.

Zinsou, who also holds French citizenship, came second to Talon in the 2016 poll but has remained in Paris in the face of his legal problems.