The Paris prosecutor's office confirmed an inquiry had been launched during last year's race over the possible use of illegal methods to aid recovery but no progress had been made.
"There has been no evolution in the case," a spokesman said, adding there were no plans to raid or search the team during the 2012 Tour, which starts in Belgium this weekend.
Europcar team leader Thomas Voeckler, who finished fourth in 2011, became a crowd favourite after wearing the leader's yellow jersey for 10 days.
Voeckler's team mate Pierre Rolland won the prestigious Alpe d'Huez stage and the white jersey as the best young rider.
News of the prosecutor's investigation was broken by French sports daily L'Equipe.
"There is nothing in it, nothing," Europcar team manager Jean-Rene Bernaudeau told reporters during a news conference in Liege on Thursday.
"It was too big for a team who has always opposed the use of corticoids," he added, referring to one illegal method of recovery.
Europcar is a member of the Movement for Credible Cycling (MPCC), a group of teams who carry out internal tests on their riders to ensure they use legal recovery methods and stay away from banned substances.
"I hope this story will make my riders stronger as it is clearly an injustice," Bernaudeau said.
Voeckler, whose participation in the Tour was confirmed this week only after he suffered a knee injury during the Criterium du Dauphine, said the team would be doing its best to put the investigation behind them as they prepared to race.
"I'm not going to tell you that you're not affected when things like that are written behind your back," Voeckler told reporters.
"It's a pain when unjustified rumours are spread but I'm focusing on my health."
The Tour de France, an event often marred by doping scandals, starts on Saturday with a 6.4-kilometre prologue in Liege.