This will be Arsenault's first appearance before the Charbonneau commission, although the inquiry has heard him in dozens of wiretap recordings. Arsenault was elected to the federation's top job in 2007 but announced in November that he would not seek re-election.
Last week, the inquiry heard a recorded conversation between senior union officials.
In wiretap evidence from 2009, Arsenault can be heard promising another union official that he had spoken to Premier Pauline Marois, who was the leader of the official Opposition of the time, about preventing the corruption inquiry from happening.
In the recordings, Arsenault also mentions a "deal" he has with Marois's husband, Claude Blanchet.
Blanchet directed the FTQ's Solidarity Fund between 1983 and 1997.
Arsenault will also answer to whether he tried to cover up a system of collusion at the union, and face questions about his relationship with construction boss Tony Accurso.
The former FTQ president fought hard to block the inquiry from using the wiretap evidence, which was recorded by police.
The union effectively lost that battle in October, when a Superior Court justice refused an appeal for more time to make a case against the release of the wiretap evidence.