Gillet, who has won nine caps for Belgium, was one of 20 individuals suspended in relation to two matches involving Bari in Serie B in 2008 and 2009, where he was playing at the time. At 34, the decision could mean the end of his career.
Bari ensured a mid-table finish when they lost 1-0 at home to Treviso in one of their final matches of the 2007/08 season and made sure of promotion when they were beaten 3-2 at Salernitana one year later.
Former Bari and Salernitana player Massimo Gancio and former Salernitana director Cosimo D'Angelo were given the longest bans, four years each.
Former Bari player Gianluca Galasso, currently out of contract, was banned for three years and seven months while another 10 players, most of them now out of contract or retired, were suspended for three years and six months each.
A further six players were given six-match bans while the tribunal agreed plea bargains with another nine, resulting in bans ranging from just over three months to 16 months.
Two players were acquitted and Bari were docked one point for next season in a plea bargain.
Italy has been hit by a wave of match-fixing allegations with police investigating cases in Cremona, Bari and Naples.
Last year, four players were banned over suspected match-fixing involving several Bari matches in Serie A in the 2010-11 season, when they were relegated.
They included former Bari defender Andrea Masiello who was banned for 26 months for match-fixing. He scored an own goal in the 2-0 defeat by Lecce, one of the matches under investigation.
Siena, Atlanta, Sampdoria and Torino all began Serie A with points deductions last season relating to earlier match-fixing cases while Juventus coach Antonio Conte was banned for 10 months, later reduced to four, for failing to report match-fixing when he was at Siena.
Conte was in charge of Bari from 2007 to 2009 but did not face any charges relating to their two matches.
Last week, the FIGC prosecutors referred Serie A clubs Lazio and Genoa, lower-league side Lecce and eight players to its disciplinary tribunal over allegations of match-fixing in the 2010/11 season.
The matches under investigation are Lazio's final games of the 2010-11 season when they beat Genoa 4-2 at home and Lecce by the same score away.
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