The French rugby league side withstood a second-half fightback to get their European Champions Cup campaign off to a 26-18 victory in Dublin.
The French, who returned to full strength after playing two internationals in one day last weekend, thought they had the match sewn up at half-time when they led 26-0.
Ireland mounted a seconed half fought back to restore pride but cannot now reach the final.
The French will win their group if they defeat Scotland in Narbonne next Saturday and will firm as favourites to meet either England A or Wales in the decider at Warrington on November 16.
Ireland were up against it for most of the first half after finding themselves on the wrong end of a 5-1 penalty count.
Centre Claude Sirvent scored two tries and others came from former Wakefield full-back Freddie Banquet, veteran forward Pascal Jampy and stand-off Laurent Frayssinous, who also kicked two goals, with the other conversion coming from Sirvent.
Ireland coach Daryl Powell sent on all four substitutes at the start of the second half and the changes helped turn around their game, although it took them 18 minutes to score their first try through centre Anthony Stewart.
Barrow forward James King, Leeds winger Francis Cummins and Halifax hooker Phil Cantillon also touched down but Paul Handforth missed all his three conversions before handing over to Karl Fitzpatrick, who was successful with his one attempt.
"Turning around 26-0 down was a big ask but to score 18 unanswered points was something to be proud of," said Ireland manager Phil Daly.
Winger Carl De Chenu, was among the players to catch the eye.
De Chenu, a Dubliner who has earned a contract with Sheffield Eagles, created his side's first try which sparked the fightback.