France went down to a shock 19-14 defeat to Tonga in their final Pool A fixture, and Deacon says Les Bleus could be galvanised by the result for the game at Eden Park.
“We don’t really know what sort of French team is going to turn up and that makes them dangerous,” says the Leicester Tigers lock, who won his 28th international cap in England’s victory over Scotland.
“They have great players, they have a lot of flair in the back line so it makes them very dangerous.
“We are expecting the full force of the French team. It is knockout rugby and they won’t be taking a step backwards at all.
“We have not lost, but with the performance against Georgia, that galvanised us in a way because we knew that we needed to improve.
“We went away that week and worked on things in training and we improved massively for the next week.
“France will be smarting after losing against Tonga and England v France in the World Cup quarter-finals is a huge match,” Deacon told RFU.com.