By beating New Zealand and scoring four tries (bonus point) in the process.
By beating New Zealand. To deny Ireland, France would have to beat Argentina, earn a bonus point for scoring four tries and have a better points for total.
By losing to New Zealand by seven or less points (bonus point). France would then only have to beat Argentina.
Should Ireland lose to New Zealand by more than seven points then: France could join them on five points by losing to Argentina by seven or less points or scoring four tries and Argentina could also finish on five points by beating France and scoring four tries in the process (bonus point). If the three teams finish on five points then the points for total will decide who makes the semi-finals.