Laporte has called on the seasoned campaigners, both 32, to bolster a French pack which was bullied by Scotland in last Sunday's shock 20-16 defeat at Murrayfield.
In total France made five changes with Olivier Milloud, Aurelien Rougerie and David Marty also drafted into a side which O'Sullivan warns is seeking an emphatic return to winning ways.
"France had a couple of injuries which forced some changes but they have also reacted to their disappointment against Scotland," the British & Irish Lions coach said.
"We expected there would be some sort of reshuffle and it's interesting they have brought back some of the old guard. They're circling the wagons after a surprise upset.
"It's a big game for them now - it might define their championship - and I think we'll get the full monty. There will be no quarter asked or given."
Ireland have their own demons to exorcise following last weekend's dismal performance in the 26-16 victory over Italy, and skipper Brian O'Driscoll insists only the players can set the record straight.
"There's only so much Eddie and the coaching staff can do. When we take the pitch the result is down to the team," the Lions captain said.
"We're drilled in such a way but you must put your hand up and take responsibility as a player. We have a big opportunity to do that this weekend."
O'Sullivan stressed the value of making a strong start at the Stade de France but insists Ireland must keep their composure if they are subjected to an early onslaught.
"The start is important and we must get our hands on the ball so that we can get into the game early," he said.
"Last weekend that didn't happen - we spent a lot of time defending during the first quarter and Italy got into the game before we did. If you let that happen against France it will be a much tougher day out.
"But the game can't hinge on making a good start - you want to do that but if it doesn't happen you can't just pack your tent and go home."
O'Sullivan named an unchanged side on Tuesday but has since been forced to make one alteration with prop Reggie Corrigan replacing Marcus Horan, who has been ruled out with a vomiting bug.
Corrigan, who won the last of his 46 caps during the 2005 summer tour to Japan, has gone straight into the starting line-up with Simon Best remaining on the bench.
"Reggie was starting at loosehead for us until the autumn while Simon Best has been on the bench because of his capacity to play on both sides of the scrum," said O'Sullivan.
"He's more experienced on the tighthead side so we wanted to bring in an experienced loosehead straight into a frontline game.
"A lot of experienced players hadn't made the initial squad on form but I was confident that those guys would be able to come in if we needed them."