The 45-year-old - who was left bitterly disappointed after their opening two defeats to Italy in Rome and Wales last Saturday at the Stade de France - added his side needed to be confident and daring if they were to end England's hopes of the Grand Slam.
England are on a run of three successive wins, a record defeat of the world champions the All Blacks last December and then beating Scotland and Ireland in a tight encounter last Sunday.
France, however, could be facing their first wooden spoon since 1957.
"The England game can be our Grand Slam," said Saint-André as he met up with his squad at Orly airport on Saturday.
"The English are euphoric at the moment. Everyone is favouring them for the Grand Slam and us for the wooden spoon," added Saint-André, whose target this season had been an improvement from their fourth-placed finish in his first Six Nations last year.
Saint-Andre, who replaced Marc Lievremont after the 8-7 2011 World Cup final loss to the All Blacks, said that he was relishing the challenge of beating the English on their own ground.
"We have to go there full of enthusiasm, confidence and daring," said Saint-André, who had two spells coaching in England with Gloucester and then Sale.
"We are going there totally unrestrained. What a wonderful challenge to be going to Twickenham. I am really eager to be proud of a team that is going to go there and give 120%."
Saint-André, who has blamed a hectic club schedule for the fatigue of his players in contrast to the ones that won three successive games in November, said he hoped a week's rest would have freshened up his players.
"We have players who are going to be fresh physically, therefore we are going to have good training sessions," said Saint-André.
"It is important that the group lives well together, and from that the team gives their all on the pitch."
Saint-André will announce his starting line-up on Thursday before they leave for England later that day with the match kicking-off at 5pm GMT on Saturday.