Cofidis cyclist Philippe Gaumont has admitted taking the banned substance EPO, his lawyer said on Monday.
Gaumont won an Olympic bronze in 1992
Gaumont, who was arrested last week, made the admission while being questioned by police, adding that he had supplied EPO to another cyclist.
"Philippe Gaumont has admitted to doping," his lawyer Olivier Combe said.
"He also explained some unfortunate things that are happening in the (cycling) system."
Police have questioned several riders from the Cofidis team and have seized male hormones and amphetamines, as well as EPO.
Britain's world time-trial champion David Millar is one of the members of the Cofidis team but he has not been involved in the investigation.
He said last week that the arrests were isolated cases and that the team did not have a drugs problem.
"All I can say is that it's not a Cofidis problem, and it's certainly got nothing to do with me," said Millar.
Gaumont, an Olympic bronze-medal winner in the 1992 team time trial, said he had never been asked or instructed to take performance enhancers.
But he described how "everything is put in place to encourage" their use, said Combe.
The rider only "discovered" EPO after becoming a professional, he added.
The lawyer said Gaumont also told investigators that he had given EPO to a fellow rider, who was not identified, to "help him out."
Under French law, the use of doping products is not illegal, but distributing them is.
Gaumont, who rode for Cofidis in the 2003 Tour de France, was detained last Tuesday with team-mate Cedric Vasseur as they returned to Paris from a training session in southern Spain.
Vasseur was not charged and his lawyer, Bertrand Wambeke, said on Monday that Vasseur had not admitted to using doping products.