Both sides have already made the knockout stages but the clash in Cardiff is almost certain to send the losers into a quarter-final against champions New Zealand, with a likely last-eight game against Argentina awaiting the winners.
Ireland beat France on the way to winning both Six Nations championships since Schmidt took over but flyhalf Sexton got an insight into what makes World Cups so different for Les Bleus while spending the last two seasons at Racing Metro.
“What I did get from them is the World Cup is huge over there, the Six Nations is almost like a burden on them in the middle of a Top 14 season, it disrupts their season,” Sexton told a news conference on Monday.
“It’s almost like they build for this and use players throughout the Six Nations year-on-year to have this big playing pool for the World Cup.
“You can see it from their previous results, arguably they should have won the last World Cup so we’ve got to be aware of all these things,” added Sexton.
Whereas Ireland have never progressed beyond the quarter-finals, France’s habit of peaking every four years has seen them fall just once at that hurdle and they have reached the final three times.
Echoing comments from Schmidt and captain Paul O’Connell after Sunday’s scrappy 16-9 victory over Italy, Sexton said Ireland would have to play better to win on Sunday with particular improvements needed in their discipline and defence.
“We’re pretty disappointed with a lot of aspects of our game, we’ve a lot to look at but we’re where we want to be, it’s all down to this weekend and that’s where we wanted to be at the start of the tournament,” he added.
“We know that we’re a pretty good team on our day when we play well and I don’t think we played well yesterday. We’re in no doubt that we’ll have to be at our very best to be in with a shout.”
(Editing by Tony Jimenez)