Twitches among the French camp were rising until they found some delightful touches and rediscovered their snap to blow out the margin to a victory.
Five of France's six tries came in their opening and closing 10-minute sections.
One other touchdown to Vincent Clerc in an hour was not the sort of production French coach Marc Lievremont would have demanded. Nor was there huge satisfaction from the Cherry Blossoms after the score blew out in the last stages.
First five-eighths James Arlidge collected all his side's points from two tries and kicks in a strong showing, but he and coach John Kirwan were disappointed after the late collapse.
Down State Highway One in Hamilton, the All Blacks arrived at their Hamilton hotel in time to watch the kickoff between Japan and France at Albany.
They were both good and modest in their tournament start, but probably sharper than most of the work that France, their main pool rivals, had displayed against Japan.
"I wanted consistency, and there I was not satisfied," France coach Lievremont said.
"It's not too much of a worry because we won, but it's a warning. We can and we owe it to ourselves to do better.
"We are not happy. It's disappointing, even if we won. We thought we were too good, too easy, after our first two tries.
"This kind of behaviour could have cost us dearly."
Even France's initial tries were a bit fortunate.
Former Harbour and now Australian referee Steve Walsh allowed the first when Maxime Medard appeared to be well held in a tackle while Francois Trinh-Duc claimed the next from an intercept.
The French backline had plenty of panache and their pack attended to the formal setpiece duties, but away from those areas they looked disconnected.
Japan rattled them with their persistence and sting, hooker Shota Horie, captain Takashi Kikutanu and lock Luke Thomson hammered into their forward work.
Halfback Fumiaki Tanaka was a livewire, Ryan Nicholas led a vigorous defensive line from the backs and Hirotoki Onozawa was an evasive speedster on the wing.
But in the washup it was the power of France, the ability to turn the screw and dish up team tries like the beaut to Pascal Pape deep in the game, which made the difference.
The French tight five looked competent and Dimitri Yachvili drove the match well from halfback and is a superb goalkicker.
Five-eighths Trinh-Duc and Fabrice Estebanez lacked some control before they were subbed off, both with injury, but wider out there were signs of French invention on the hard and fast track.
Captain Thierry Dusautoir was industrious but his looseforward cohorts lacked some sting in their duties.
France next play Canada in Napier on Sunday.
Japan meet the All Blacks in Hamilton on Friday.
