Letting winger George North play for Wales against the Wallabies last month cost his Northampton club a £60,000 (US$98,000) fine today.
Northampton admitted breaching Premiership Rugby policy, which allows only England players to be released for matches or national camps outside of the international test window. The league penalised the club after a hearing on Wednesday, and said in a statement that Northampton will not appeal.
North scored both of Wales' tries in the match on November 30 at Millennium Stadium, where Australia won 30-26.
When North agreed to join Northampton this year, he had a clause in his deal to be released for all tests and training camps, including any outside of the window. When Northampton released the British Lions star for the match, it said at the time that it backed him and it "has not contravened any laws, rules or regulations."
"The club's management wants every player at the club to achieve the highest level they can, and wants every player to have the ambition to wear their respective national shirt," the statement added.
"While we appreciate that we are outside Premiership Rugby board policy with this particular agreement we also believe that having George as a Northampton Saints player has benefitted both the club and the league as a whole."