Madiot, a twice Paris-Roubaix champion and now head of the French Cycling League and manager of the FDJ team, questioned a number of Sky's statements regarding an investigation into a package delivered to rider Bradley Wiggins in 2011.
Sky did not respond to Madiot's comments when contacted by Reuters on Thursday, simply saying they had nothing to add to a statement they had issued on Wednesday.
That statement came as head of UK Anti-Doping (UKAD) Nicole Sapstead told a British parliamentary select committee that there were "zero records" from the doctor who delivered the package to Wiggins at a race in France, which he won.
"It's quite surprising coming from people who are claiming to be experts in mastering details," Madiot told Reuters.
Sky, who have won four of the last five Tour de France titles, have repeatedly said they owe their success to "marginal gains". No British team won the race in its first 108 years.
Madiot's swipe is the latest spat between French and English cycling figures.
It takes little for the ancient enmity between the two nations to surface, and Britain's recent stellar success in a sport for years considered France's own has ruffled Gallic feathers.
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Wiggins angered by package questions
OLD RIVALRY
French cyclists have won the Tour de France 36 times, far more than any other nation with Belgium riders second on 18. Britain's four wins place them in sixth place.
The last French rider to win a Tour de France was Bernard Hinault in 1985. More recently Romani Bardet (AG2R) finished second overall in 2016.
Team Sky chief Dave Brailsford riled the French during the 2012 Olympics when, as Team GB's performance director, he teased his rivals, claiming to have "specially round" wheels, to explain Britain's dominance.
On Wednesday, Sky denied any wrongdoing. "Our commitment to anti-doping has been one of the founding principles of the team," Sky said in a statement. "We have worked hard to put the right governance structures in place."
The Committee were told that doctor Richard Freeman's laptop, which allegedly contained his records, was stolen in 2014.
Madiot appeared sceptical. "They are ... world champions and, awkwardly, the doctor's laptop disappears," he said.
Brailsford told the committee in December that Freeman had told him the package contained Fluimucil, a legal decongestant. Sapstead said UKAD could not confirm or disprove this.
"Why go through the trouble of flying in a product that you can buy over the counter for five euros in any French pharmacy?" Madiot asked.
Some cycling teams are reluctant to go to pharmacies during races because they fear they are under surveillance, a former anti-doping official told Reuters on Thursday, on condition of anonymity.
He added that French police are usually set up surveillance at top races, especially on the Tour de France.
British Cycling acknowledged "serious failings" in its system.
"Our medicine management processes have been reviewed several times since 2011 and ... we have identified further areas for improvement," it said in a statement.
Two weeks ago, former British Olympic champion Chris Boardman told Reuters he doubted the full truth would be known: "Clearly they are not going to get any more answers. But that typifies the last 20 years, to be honest."
