The defending Six Nations champions go into tomorrow's game on the back of eight consecutive defeats. Ireland stormed to a halftime lead of 23-3 and despite a second half revival by Rob Howley's men at the Millennium Stadium, Wales slipped to a disappointing 22-30 defeat.
"In comparisons with the standards we have set as a team, that first half-hour was very disappointing and it cost us the game. It is one of the worst Wales performances I have ever been involved in," conceded the Cardiff Blues midfielder.
"Saturday night hurt. I could see it on the faces of all the boys. The fact is, if we defended better in the first 20 minutes we would have won the match. But we were 20 points down before we touched the ball.
"It is hugely frustrating because we all know the structure is there for us to win rugby games but we made the wrong decisions on the ball against Ireland.
"We all know that where there are chances to score tries there are chances to win games and we know we can cause France problems on Saturday."
Wales have not won in France since a Grand Slam-winning campaign back in 2005 . Roberts will come face to face with big hitting Mathieu Bastareaud will be making his first start for France in nearly three years after being named in Philippe Saint-André's side to take on Wales.
The powerful centre last started for les Bleus in 2010, when they won the RBS 6 Nations Grand Slam, but returned to the French matchday squad for the defeat in Italy.
His Toulon teammate Jocelino Suta, who missed the game in Italy, comes straight into the second row for the injured Pascal Papé as France's second change, with Thierry Dusautoir taking over the captaincy.