The French anti-doping lab that tested American cyclist Floyd Landis' urine samples made an ``administrative error'' when reporting its findings on his backup ``B'' sample, the French newspaper Le Monde reported Wednesday.

The newspaper cited unnamed sources as saying the Chatenay-Malabry laboratory gave the wrong number in its report about Landis' second sample. Tests on the rider's two samples indicated that Landis had elevated levels of testosterone in his system when he won the Tour de France in July.

In its report, the lab wrote that the ``B'' sample tested was number 994,474, while the actual number was 995,474, Le Monde said.

``The error, of an administrative nature, does not mean the positive B sample was not that of the American,'' Le Monde said. ``But it is being used today by his lawyers ... to contest his positive doping results.''

Contacted Wednesday by The Associated Press, the lab referred questions to the French anti-doping agency. The agency's secretary general, Philippe Dautry, declined to comment on the report.

Landis' lawyer, Howard Jacobs, has already alleged that the French lab made repeated errors in its analyses, including mismatched sample code numbers.

In a letter sent to the U.S. Anti-Doping Agency in September, Jacobs said the positive finding on the ``B'' sample came from a sample number not assigned to Landis.

``It's incredibly sloppy,'' Jacobs said at the time. ``It has to make you wonder about the accuracy of the work.''

On Sunday, Landis said in a French television interview that the lab made crucial errors in his tests.

``Even the best people make mistakes,'' he said. ``I can't say that the lab is always a bad lab, but I can say that in this case it made some mistakes ... I did not take testosterone.''

Le Monde's report came a day after French authorities said they are investigating a complaint that hackers stole data from computers at the same lab in an attempt to discredit the lab's credibility.

Tour de France organizers no longer consider Landis the Tour champion. He will contest the test results at an arbitration hearing in the United States. If found guilty of doping, he would be formally stripped of the title and face a two-year ban.