England coach Gary Street admitted he never doubted his team would seal the Grand Slam despite being pushed all of the way by France.
Katy McLean’s second-half penalty proved to be the clincher in the 11-10 win as the hosts France battled bravely following the first-half sending off of Claire Canal.
Amy Turner’s first-half try gave England a 5-3 half-time lead but France hit back after the break to go ahead thanks to Céline Allainmat’s converted try.
That gave France a 10-8 lead before McLean kicked the final points of the game with a 64th minute penalty.
And Street said: “Even though this was a tight game, the victory was never in doubt in my mind.
“We knew France would throw everything they had at us and they made us work very hard for this win.
“But we showed great character and mental strength to turn it around.
“This is great World Cup preparation for us. We need tough games and France gave us exactly that.
“Now it’s back to work as we look ahead to the World Cup which we just can’t wait for.”