Abba Abacha, a son of former dictator Sani Abacha, has rejected the decision of a Geneva judge to impose a prison term for participation in a criminal organisation.
The initial judgment of November last year would only have stood if uncontested by the 41-year-old Nigerian. The case will now go to trial.
At stake is $350 million (SFr355 million) in Abacha funds in Luxembourg and the Bahamas which was confiscated by the investigating judge in the course of the investigation.
The Geneva investigation of the Abacha case began ten years ago. General Sani Abacha, who died in June 1998, was accused by Nigeria of having stolen billions of dollars of state funds for himself and his family during his time in power.
Hundreds of millions of dollars previously blocked in Swiss banks in relation to this affair have already been returned to Nigeria.
swissinfo.ch and agencies