Stricken fly-half Jonny Wilkinson remains a major doubt for that Stade de France showdown after suffering an ankle ligament sprain during training earlier this week.
The England camp are saying little about his condition until next Tuesday, and Wilkinson's enforced absence must be put out of their minds for a Pool A encounter they will be expected to win by at least 50 points.
Medical opinion from outside the England squad suggests Wilkinson could be sidelined for six weeks, ending any chance of him playing in the World Cup.
Ashton said: "Jonny is being assessed again next Tuesday. I have seen the speculation, and I have made no contact with anyone about being on stand-by.
"There is a possibility he will be fit for South Africa. We will need to know the situation on Tuesday, because that is three days before the South Africa game."
Saturday's game is the 41st on England's schedule since they were crowned world champions in Sydney almost four years ago.
But just 16 victories - a 40% success rate - underlines the extent of their demise, which is confirmed through an official International Rugby Board world ranking of seventh.
They also arrive in the tournament after failing to score a try during home and away warm-up games against France, raising acute concern about England's inability to break down world rugby's best defences.
Ashton added: "We are looking for a little more accuracy than we have shown recently, and if we can also get through the game without injuries then we will be pretty satisfied.
"We have analysed the opposition because it would be disrespectful not to, but we've focused a great amount of our attention on our own game. We are not in a position to do anything else.
"If you start thinking about racking up a specific number of points, you put yourself in dangerous territory. The important thing is to get the key processes right.
"I have full confidence the players will rise to the occasion."