FRANKFURT, Germany — The German cycling federation has begun proceedings aimed at banning Stefan Schumacher after confirming Tuesday that the Tour de France stage winner tested positive for blood doping before and during the July race.

The federation said it would pursue "the longest possible ban," two years.

Gerolsteiner, which had suspended Schumacher on Monday, said blood samples taken on July 3 and July 15 from the rider tested positive for CERA, an advanced version of the blood booster EPO, according to documents provided by the federation.

The tour started July 5 and ended July 27. Schumacher won both individual time trials in the race. July 15 was a rest day.

The cycling federation said Schumacher had five days from receiving official notification of the positive test to give a statement or ask for a B sample test.

Schumacher's lawyer Michael Lehner said he had not received the documents yet.

Another stage winner, Leonardo Piepoli of Italy, also tested positive for CERA. Italian cyclist Riccardo Ricco has already admitted to CERA use.

The French Anti-Doping Agency has been retesting blood samples from the race in a bid to catch more cyclists they suspect may have used CERA. The original urine tests had cast a shadow of doubt over several riders but proved inconclusive.

The French agency informed its German counterpart about Schumacher's positive test and they gave the information to the cycling federation.