France's Fabrice Estebanez, left, is tackled by Ireland's Felix Jones, right. (AP Photo/Peter Morrison)
Jones fell awkwardly in the 26-22 loss and must keep the foot immobile for six weeks.
The 24-year-old fullback was playing in only his third international appearance after he debuted against Scotland this month but had a chance of making Ireland's 30-man World Cup squad.
Ireland manager Paul McNaughton said Sunday that Jones "certainly put himself into contention over preseason and the games in the last three weeks."
Jones may also need surgery after further checkups.
Ireland plays its first World Cup match against the United States on September 11.