Castrogiovanni launched a scatching attack on former club Leicester Tigers and coach Richard Cockerill after the French club's 25-21 defeat at Welford Road on Sunday.
The Italian hit out at his treatment before he left the club for Toulon, specifically criticising Cockerill, with the Leicester boss later calling for an apology from the 33-year-old.
EPRC's disciplinary officer has now filed a complaint against Castrogiovanni and a hearing has been set for December 17.
"The misconduct complaint against Martin Castrogiovanni is that after the match he made a number of comments to the media in which he attacked, disparaged, criticised, damaged and/or brought into disrepute Leicester Tigers, the club's director of rugby, Richard Cockerill, EPCR, the European Rugby Champions Cup and the sport of rugby union," read an EPCR statement.
Castrogiovanni's team-mate Delon Armitage has also been charged for unsportsmanlike conduct during the same game.
"During and after the match he is alleged to have conducted himself in an unsportsmanlike manner by making a number of comments to, or within earshot of, spectators using foul and abusive language," EPCR added.