In December, the leader of the Constitutional Council, Paul Yao N'Dre, ratified Laurent Gbagbo as the winner, leading to a four-month stand-off.
Mr Gbagbo has reportedly been questioned for the first time about rights abuses while he was in power.
However, his French lawyers have been blocked from attending.
They were refused entry to Ivory Coast at Abidjan's airport and reportedly put on the next flight back to Paris.
A UN team is investigating the site of an alleged mass grave in the Yopougon district of Abidjan.
A spokesman for the UN High Commissioner for Human Rights says it has received reports of human rights abuses by both sides in the area, which was taken by pro-Ouattara forces earlier this week - the last pro-Gbagbo holdout in the country's main city.
