Graham Rowntree has warned England to expect a gruelling battle against a wounded France side on Saturday at Twickenham.
Defeats in their opening two Six Nations games have heaped pressure on the French, but Rowntree believes Philippe Saint-Andre's side will be determined to upset the hosts' Grand Slam hopes.
The forwards coach is wary of the challenge posed by France's imposing pack and is planning for the return of loosehead prop Thomas Domingo to the front row.
"Philippe Saint-Andre is already saying this is their Grand Slam," Rowntree said.
"It will change the whole complexion of their championship if they win at the weekend and the way they will challenge us is through their forward pack.
"There is never a weak French scrum. We are preparing for Domingo. I think he will start.
"We have been watching him play for Clermont. He has been around that set-up for a few years now. He is an incredible scrummager, a compact little unit but technically very good.
"As an outfit, regardless of results, that area of the game is something we always respect with France."
Rowntree and head coach Stuart Lancaster face a selection dilemma, as Mako Vunipola staked his claim for the loosehead prop role with a fine display in Saracens' Aviva Premiership victory over Exeter at the weekend.
Harlequins' Joe Marler has been a regular starter, with Vunipola being used as a replacement, but Rowntree admits it is hard to pick between the two.
"He played well (against Exeter) didn't he? He has been one of the real breakthrough players of the season so far," Rowntree said.
"I am delighted with his progress. He demonstrates the strength we have got in many positions.
"I remember myself as a prop coming on and trying to get up to the pace of the game, trying to make an impact on the game and he does it better than I ever did.
"Who we start, it's no bad thing for a person like him to sit on the bench. What I mean by that is he could start, I'm quite comfortable with him starting. It is horses for courses."