French rugby club Grenoble have been deducted four match points and fined 10,000 euros ($A12,480) for fielding an ineligible player against London Welsh in a European Challenge Cup Pool 5 encounter last Friday.
Grenoble admitted the misconduct charge for fielding Australia's Lotu Taukeiaho in the fixture.
Taukeiaho was not registered with European Rugby Cup (ERC) as a member of Grenoble's tournament squad and was therefore an ineligible player.
Grenoble won the game 20-9, but London Welsh have been awarded a 28-0 victory and five match points after an independent disciplinary committee hearing on Thursday.
It means London Welsh move from third to second in the pool, three points above Grenoble, and five behind group leaders Stade Francais.
"The hearing was based on written submissions made by Grenoble, who pleaded guilty to the misconduct charge, and by ERC's disciplinary officer Roger O'Connor," ERC said in a statement.
"After considering the submissions, the independent disciplinary committee, which was chaired by Roger Morris (Wales) with Rod McKenzie (Scotland) and Jeremy Summers (England), determined that the selection and subsequent participation of Taukeiaho in the match contravened the 2012/13 Challenge Cup tournament rules. Both Grenoble and ERC have the right to appeal the decision."
London Welsh and Grenoble meet in the return fixture at Oxford's Kassam Stadium on Saturday.