Gallic unpredictability adds a special dimension to world rugby with the French themselves unable to predict with any confidence what performance they will produce on a given day.
What is certain is that France cannot afford to leak three tries to England in Saturday's pivotal Six Nations match at Twickenham as they did in the opening round against the Scots. Nor will they want to concede a try after only four minutes as they did two weeks ago against Ireland.
France still joined England as one of only two teams to emerge unbeaten from the first two rounds and an early hint of spring in the air after a bitter English winter should lift the spirits of the grand slam champions, who flourish when the sun is shining and the ground is firm.
But France are also uneasily aware that they have not won a championship game at Twickenham since 2005 and they will meet an England side brimming with confidence after disposing of Wales and thrashing Italy.
Five changes to a winning team for Saturday's match reveal more about coach Marc Lievremont's thinking than some provocative remarks about ancient enmities this week.
Lievremont dominated the headlines when he said France, Italy and the Celtic nations shared a common dislike of England.
This hardly came as news to England manager Martin Johnson. who pointed out that the historic antagonisms did not just involve the rugby pitch. Otherwise, as in his playing days, Johnson made it clear that he preferred deeds to words.
Before the championship began Lievremont signalled he had brought an end to the bewildering number of selection changes which have characterised his period in charge of the national team.
CHABAL TO START
The 30-man squad for the Six Nations, said Lievremont, would differ little from the one named next month for the World Cup in New Zealand this year.
This, though, has not precluded Lievremont from changing his starting lineup for Twickenham.
Lievremont has opted for the ferocity and strength of Sebastien Chabal at number eight with Imanol Harinordoquy moving to the side of the scrum.
Another noted French warrior, centre Yannick Jauzion, makes his first start of the championship while Lievremont has also gone for experience at scrumhalf with Dimitri Yachvili starting ahead of Morgan Parra. Five changes would have been six had Maxime Medard, who had been switched from wing to fullback, not withdrawn on Friday with a hamstring injury.
"I think that there will be a lot of rhythm and intensity in the match and again the bench will be important," Lievremont said. "I don't have the feeling that I'm taking risks."
Before the first World Cup in 1987, also staged in New Zealand, France swept England aside at Twickenham with a wonderful display of brute power in the forwards and high skill and pace in the backs.
They duly won the grand slam and went on to defeat Australia in one of the great matches in the World Cup semi-finals before losing to the All Blacks in the final.
To the neutrals, the 2011 French team are also stronger man-for-man than England. They possess a magnificent row, powerful locks, a mobile backrow and dangerous running backs, who have yet to fire this year.
But which France will turn up at Twickenham? The team who strode to the grand slam last year or the abject bunch who capitulated 59-16 to Australia in November?
If it is the former, France could take a big step towards a second grand slam and give added substance to their dream of winning the World Cup for the first time.