L'Équipe said the multi-year investigation had ended after finding "nothing" and the issue had been "dismissed".

An inquiry involving two financial magistrates, supported by the financial crimes division of the French police, was launched in 2017 after claims mechanical doping had infiltrated the "highest level" of cycling.

It was said to have benefited "big-name riders" and allowed them to "take advantage of the latest technological advances in the field of electric motors".

However, Belgium's Femke Van den Driessche remains the only high-profile rider to have been caught after a concealed electric motor was discovered on her bike at her home Cyclo-Cross World Championships in Heusden-Zolder in 2016.

Van den Driessche, who was competing in the under-23 event, was later banned for six years by the International Cycling Union (UCI).

France's UCI President David Lappartient spoke strongly about the threat of "technological fraud" during his campaign for the top job, which culminated in victory over British incumbent Brian Cookson in September 2016.

Reacting to the L'Équipe report on Twitter, Cookson said: "You'll have to allow me a wry smile about this."

The UCI started carrying out unannounced bike checks in 2016, with scanners used in a bid to detect motors.

Thermal cameras have also been used, as well as a mobile x-ray unit.

In 2017, Jean-Christophe Péraud was appointed as the governing body's manager of equipment and placed in charge of the fight against technological fraud, in another sign that the organisation was taking the issue seriously.

At the 2018 Tour de France, a thermal device picked up a "burst of energy" from a rider's pedals but it turned out to be a false alarm caused by a mechanical defect. 

Switzerland's double Olympic gold medallist and four-time world champion Fabian Cancellara was accused of mechanical doping by Italy's Davide Cassani in 2010, a claim he strenuously denied.

The UCI said there was no case against him.