Speaking on his website, the seven-times Tour winner stated tersely that the "witch-hunt continues" and the article is "nothing short of tabloid journalism". According to L'Equipe, six of Armstrong's urine samples he provided to anti-doping officials during the 1999 Tour showed "unequivocal" indications of EPO use.
Armstrong's alleged consumption of EPO was timed, the paper claimed, to coincide with three critical periods of the Tour.
L'Equipe argues that the American took EPO before the prologue - which he won - and then before the Alps and Pyrenean stages, where he sealed his overall victory.
Why the story has taken so long to emerge is that at the time there were no tests for EPO, a substance which boosts red-blood cell production and which was synonymous with the scandals that nearly brought the 1998 Tour to a premature halt.
However, samples were kept and a test developed - first used in the 2000 Olympics - which prompted a Paris-based laboratory to begin re-testing.
L'Equipe has published what it claims to be a paper from the World Anti-Doping Agency accredited laboratory, which statessix uses of EPO by Armstrong.
The American's response has been in his usual terse, laconic line to accusations of illegal drug use - which have never been lacking during his seven straight Tour wins since 1999, but never actually contained more than circumstantial, inconclusive, evidence.
"I will simply restate what I have said many times: I have never taken performance-enhancing drugs," said Armstrong, who retired from the sport this summer.
With battle lines between those believing Armstrong and those who feel there is room for doubt already well-established, support for L'Equipe's report came quickly from the French Sports Ministry.
"Athletes who want to cheat will now be under permanent pressure anywhere in the world," the French minister for sport, Jean-François Lamour said.
"This is sad, but it's also a great step forward in the fight against doping."
Defence of Armstrong came from the world's greatest ever cyclist, Belgian Eddy Merckx. "If I had to take a journalist's word or Armstrong's, I'd take Lance's," Merckx said.
Among those arguing that more time should be taken before condemning Armstrong is the director of the Tour de France, Jean-Marie Leblanc. He stated that even if the report was "meticulous and well-structured", Armstrong's directors and doctors should be allowed an opinion. However, when asked if he felt disappointed by the American, his answer was "yes".
One question raised by the report was whether a test of seven-year-old samples could be accurate, something confirmed by the laboratory director Jacques de Ceaurriz.
De Ceaurriz did, however, refuse to confirm that the figures published by L'Equipe corresponded to Armstrong's urine samples.
Other unanswered questions concern the identity of up to six other Tour riders L'Equipe also claims tested positive or EPO in 1999, and the nature of Armstrong's longer-term reaction.
Disciplinary action is extremely unlikely, given that the laboratory only released the paper to Wada on condition they did not use them for sanctions.
What is beyond doubt in the wake of this latest affair, is that the pro- and anti-Armstrong camps are pitched even further apart than ever before.Reuse content