The French public prosecutor in Tahiti, Jose Thorel, says a French Polynesian businessman, who hade been held overnight, was being questioned about the way he obtained public sector contracts under a previous government.
Coco Taputuarai was also questioned about his financial links to the Tahoeraa Huiraatira Party of Gaston Flosse.
Mr Thorel made the disclosure to Tahitipresse after the businessman's release and after his home had been searched by investigators who have seized documents for analysis.
Mr Thorel has also confirmed that the interrogation of a former assembly member, Noa Tetuanui, was linked to alleged corruption involving the Tahoeraa five years ago.
In 2004, Mr Tetuanui quit the ruling coalition led by Oscar Temaru to give the one vote needed for a no confidence motion to succeed.
Mr Tetuanui has not been charged but says he expects to be summoned over the allegations.
Since July, there has been a surge in detentions and searches linked to alleged corruption in the latter years of the Flosse administration.