Gloucester have received a suspended two-point deduction and were also fined £5,000 for breaching Aviva Premiership Rugby Regulation 3.3(a).
In the Premiership match against Sale Sharks on March 29 the club selected Mariano Galarza, who did not hold effective registration for Gloucester.
An independent panel of Jeremy Summers (chair), Bonike Erinle and Robert Horner imposed the sanction – suspended until the end of the 2016-17 season – and the fine, which is payable immediately.
Summers said: "The recommended sanction for a breach such as here, which involved an administrative error as opposed to an attempt to gain a competitive advantage, is a deduction of two league points.
"The Panel felt that there were circumstances specific to this case which meant it was appropriate to suspend that deduction.
"However, should there be another breach of relevant regulations before the end of the 2016-17 season the deduction will be imposed in addition to any other sanction required at the time."