Flood, who started at centre with veteran Jonny Wilkinson preferred at fly-half in Saturday's quarter-final, accepts England looked lost during a disastrous first-half which saw France take a 16-0 lead into the break.
Tries from Vincent Clerc and Maxime Medard stunned England and despite second-half scores from Ben Foden and Mark Cueto, Martin Johnson's men failed to turn the tide.
And after jetting back to home off the back of a 19-12 defeat, the 26-year-old Leicester Tiger insisted England must be smarter if they're to make amends in four years time.
"They were smart, I think they out-thought us, especially in that first 20 minutes, and when they went 6-0 up it fuelled their fire and allowed them to force their hand in the game," he said.
"We were chasing our tails a bit in the first half and I think it's important we realise that, in these games, we have to engage our brains and engage our bodies in terms of what we're doing.
"Sometimes we look to one another for cues and timings of things whereas other teams are just flying around and hitting us."
Victory over France, who England defeated during their victorious 2011 RBS 6 Nations campaign, would have seen them face Wales in at the semi-final stage.
But after failing to make it through to the last two weekends of the World Cup, Flood admitted heading home despite avoiding the Tri-Nations giants was all the more galling.
"We have fallen short - we haven't even made the last two weeks of the tournament," he said.
"You are going to come here aiming to win it and when we saw the draw we thought, 'Yes, we've beaten France this year' and, 'Yes, we've beaten Wales this year', so there was a chance for us and we have fallen short because we haven't achieved the goals we set out to achieve.
"It's difficult to put into words how hard you've worked and how disappointing it is not to achieve your goals."