In a report that runs to almost 100 pages, the former Harlequins director of rugby is criticised for masterminding the faked blood injury to wing Tom Williams during a Heineken Cup game against Leinster in April.
"Mr Richards was the directing mind and had central control over everything that happened in relation to the fabrication of the blood injury on the pitch and the cover-up in the days after the match," said the appeals committee in a statement.
Last month former England forward Richards was suspended from world rugby for three years after the International Rugby Board governing body said the ban previously handed out by the ERC for staging the injury was global.
The only aspect of the April incident in which the appeals committee said Richards did not have direct involvement was the alleged cutting of Williams's lip by Dr (Wendy) Chapman.
Harlequins escaped further punishment last month from the Rugby Football Union (RFU) despite evidence they faked blood injuries on four additional occasions to the high-profile one they have already been disciplined for.
Williams, who was replaced by specialist goalkicker Nick Evans near the end of the April game, received a four-month ban while physio Steph Brennan was suspended for two years.
The club was also fined 300,000 euros by the ERC. The ERC board said Harlequins would not be thrown out of this season's Heineken Cup.
Quins have been drawn in Pool 5 with Toulouse, Cardiff Blues and Sale.