The clash at Lansdowne Road is crucial to the defending champions' title defence after they lost their opener 25-17 to England last month before thrashing Scotland 38-3 two weeks ago.
The Irish, who have won their past two away games over Scotland and Italy, have not won a Grand Slam since 1949 and will be eager to keep that goal in sight as they clash with France in Dublin.
"This match implies for us as much pressure as there was against England, if not more," Magne said. "This is the last biggest clash for us before the summer tour in New Zealand and Argentina.
"Either we win and we are still in the race for the title or we lose and we are sidelined, with the consequences and doubts this may imply.
"Without insulting Italy and Wales who we will face subsequently, I think this match is the last real big showdown for us together with the match with New Zealand, whom we play in June ahead of the World Cup.
"It will also have a huge importance in terms of how to cope with matches away from France."