England head coach Simon Middleton says it is "hugely important" that France remain competitive as his side seek a seventh successive win against their closest Six Nations rivals.
France last beat England in 2018, the year of their last Six Nations title.
With the two sides meeting again on Saturday, Middleton hopes Les Bleues can again reach past heights to aid 2021 World Cup preparations.
"It's hugely important that they stay as strong as they can be," he said.
"And that the other nations endeavour to get stronger. I wouldn't say they're not competitive because a lot of the games have been competitive."
England beat France 33-10 in Grenoble last weekend and now face them again at Twickenham - in a match you can watch live on BBC Two.
In Thursday's World Cup draw they were both placed in Pool C, but the biggest challenge in next year's tournament lies in attempting to dethrone defending champions and hosts New Zealand.
Back-to-back Grand Slam champions England are only scheduled to take part in the 2021 Six Nations - where France are the only real threat to the title - before then.
England's World Cup experiments
After being drawn in the same pool as France, Saturday's match takes on a new significance as a World Cup rehearsal.
England are testing their strength in depth 10 months out from the tournament with an experimental line-up.
Katy Daley-Mclean takes on the captaincy in Sarah Hunter's continued absence and in the centre England are trying their luck without Women's Six Nations player of the championship Emily Scarratt.
Lagi Tuima will instead be given an audition at 13 as Middleton looks to avoid becoming "over-reliant" on Scarratt before the World Cup.
"Emily's brilliance could be a threat as much as a strength for us if we become over-reliant on her," he said.
"If she is unavailable we'll have questions that we don't know how to answer at the wrong time. So this week we are taking the opportunity to look at Lagi."
Same players, new positions
Wing Jess Breach is out with an adductor injury and scrum-half Claudia MacDonald shows her versatility as she moves out to cover the Harlequins flier.
But Poppy Cleall is the most versatile player of all as she moves into her fourth position in an England shirt.
The Saracens forward will line up at number eight against France, having previously played prop, lock and flanker for her country.
"Poppy is outstanding in each position," Middleton said.
"I don't think there is a more knowledgeable player in our squad. She could be one of the best players at the World Cup."
Line-ups
England: Kildunne; MacDonald, Tuima, Harrison, Dow; Daley-Mclean (capt), Riley; Cornborough, Davies, Brown, Ward, Talling, Millar-Mills, Matthews, Cleall.
Replacements: Cokayne, Perry, Keates, Beckett, Packer, Hunt, Rowland, Scarratt.
France: Izar; Banet, Pignot, Ulutule, Bertrand; Drouin, Sansus; Deshaye, Sochat, Bernadou, Ferer, N'Diaye, Mayans, Hermet (capt), Gros.
Replacements: Touye, Traore, Joyeux, Diallo, Menager, Bourdon, Peyronnet, Tremouliere.