The Olympic, world and European champions were undone by five stunning long-range strikes from Mariama Signate in the first half, Alexandra Lacrabere taking over in the second period with three of her own.
Paule Baudouin's five goals were also decisive though coach Olivier Krumbholz lauded the heroics of Amandine Leynaud in goal as France, who led 17-12 at the break, withstood a fightback.
"We relied on the goalkeepers and posts a bit too much.
Amandine was terrific. Without her, our efforts in the first 40 minutes could have gone to waste," he said.
"With so much effort up to the final stages it would have been a shame not to have won," he added, his team having withstood a last-gasp Norway attack a player light after Lacrabere was sent to the bench for a defensive foul.
France's fast start handed them a 3-0 lead after three minutes from and they never looked back, forging 6-1 ahead with Norway's solitary goal coming from Heidi Loke as Leynaud repelled everything in sight.
Loke said the team need a talking to after their woeful first-half performance.
"We turned this terrible play in the first half around to play well in the second half, but we have to improve this as it's not good enough," she told Reuters, smiling despite the defeat.
2008 Olympic bronze medallists South Korea top Group B following a 31-27 win over Spain with three-times champions Denmark also on two points after their 21-18 defeat of neighbours Sweden. France lie third on two points.
"This group is going to be very, very, very difficult," added Krumbholz, refusing to get too excited.
Gold medal contenders Russia fared better than Norway in their opening match with a 30-27 win over Angola to sit second in Group A.
The Beijing silver medallists were never really threatened despite Angola levelling in the second half while hosts Britain plunged to a dismal opening 31-19 loss against fellow debutants Montenegro and Brazil beat Croatia by a solitary point.
- Amandine Leynaud
- Olivier Krumbholz