An independent disciplinary panel decided to suspend 50% of Cheika's fine until June 30, 2013 on condition that he faces no further misconduct charges during that period.
Cheika admitted making disparaging comments to match officials both at half-time and immediately after the final whistle at the Cardiff City Stadium.
The former Leinster boss also pleaded guilty to making offensive remarks to an employee of tournament organisers European Rugby Cup Ltd after Harlequins had snatched a late 19-18 victory.
The independent disciplinary committee was chaired by Simon Thomas (Wales) and also comprised of Mark McParland (Ireland) and Antony Davies (England).
Thomas said: "In reaching its decision, the independent disciplinary committee had at the forefront of its mind one of the core values of rugby, that of respect, which match officials and others involved in the game are entitled to be shown at all times."
Cheika was fined a total of 15,000 Euros for the first charge and 5000 Euros for the second, with half of each suspended for two years.
Cheika was also found liable for the costs of the hearing.
Both parties have the right to appeal against the decision.