A French court was due to consider on Wednesday a request to extradite a Beninese businessman accused of plotting to poison President Thomas Boni Yayi.
Patrice Talon is accused of being behind a conspiracy to assassinate Boni Yayi during a coup attempt last year. He is also accused of economic crimes.
France's appeal court has a Beninese report of several hundred pages to consider, having demanded clarification of seven points when it considered the extradition request in May.
Talon, who is in exile in France, is accused of being the brains behind an assassination plot that allegedly involved Boni Yayi's niece, Zoubérath Kora-Séké on Wednesday, and his doctor Ibrahim Cissé.
Benin also wants the extradition of Talon's collaborator, Olivier Boko, who has also fled abroad.
France cannot extradite anyone to a country where the death penalty and forced labour are still in operation, which is the case in Benin although they are supposed to be abolished soon.
The French judges wanted to be informed of what punishments would replace them.
They also asked to see reports by the US's FBI and French laboratory Toxlab on the pills that were allegedly used in the plot, following reports that they had been tampered with, and requested mpre details of the time and place of the alleged assassination attempt.
They have been presented with transcripts of about 20 "incriminating" SMSs between Talon and Kora-Séké.
Opposition politicians have accused the government of inventing the conspiracy in order to launch a purge.
Last May Beninese judge Angelo Houssou dismissed charges of attempted assassination against Talon and his associates on the grounds that the poisoning did not take place.
On the same day as his ruling he was detained trying to leave the country and placed under surveillance at his home in Cotonou.
Benin has also brought cases against Talon for influence-peddling in Brussels and in Geneva for money-laundering.