Les Bleus spluttered their way into the knockout stages of the competition after a shock loss to Tonga on Saturday.
"I would never say that France look weak," said the number eight. "They are always very passionate, always very tough, and everyone raises their game to try to beat the English, as we saw again against Scotland.
"Their last two results don't matter - we've got to respect them, and make sure we concentrate on being at our best, believing they will be on top of their game too.
"I'd be surprised if they didn't come at us hard, and offer a big challenge. If you look at their team they're all outstanding individuals."
The last encounter between the two teams was at this year's Six Nations, which England won 17-9.