Rohan Janse Van Rensburg has been fined and banned for two weeks after signing playing contracts for both Sale and Gloucester, while the Sharks have been handed a suspended five-point deduction for their role in the saga.
The South Africa centre joined Sale on a permanent basis ahead of the 2018-19 season after a loan stint but the RFU revealed he had also signed a deal with Gloucester.
Van Rensburg was charged with conduct prejudicial to the interests of the game contrary to RFU rule 5.12, while Sale were charged with breaches of RFU regulation 7.5 relating to approaches to players. The RFU said both club and player accepted the charges.
The dates of Van Rensburg's two-week suspension will be determined once more details of the playing calendar become available. A fine of £32,500 has also been levied, of which £25,000 will go to Gloucester to reimburse the Premiership club for monies which were given to Van Rensburg but not repaid.
Sale, meanwhile, were given a suspended five-point deduction for the next two seasons on condition they do not breach RFU regulation seven during that time, while they have also been fined £20,000.
"There is a right of appeal against this decision," the RFU added in a statement.