A spate of recent doping scandals, some of which involved German and Austrian riders, prompted ARD and fellow German broadcaster ZDF to announce their intention not to stop broadcasting the world's biggest bike race.
But on Tuesday Fritz Pleitgen, the president of the European Broadcasting Union (EBU) which represents 75 public broadcasters, said ARD was tied by its current contract with ASO, the company which own the Tour.
Pleitgen said ARD, and fellow German broadcaster ZDF, had acquired the television rights from 2009-2011 alongside a group of around 10 other public channels - and would have to honour it.
"ARD, in conjunction with ZDF, signed a contract last January that covers the period from 2009-2011 for a total of six million euros a year," Pleitgen said Tuesday, adding that ARD's attempt to break its contract was "against the rules" of the EBU.
Pleitgen said both ARD and ZDF had included clauses in their contract which demanded that Tour organisers employ "the most modern anti-doping controls" available. "If these conditions are not respected by the organisers, the television channels can end their contract once it becomes valid on January 1, 2009," added Pleitgen.
A total of seven riders from this year's race have tested positive, four of whom - Italians Riccardo Ricco and Leonardo Piepoli, German Stefan Schumacher and Austrian Bernhard Kohl - for the latest generation of blood-boosting EPO (erythropoietin) called CERA.
Although attracting further scandal to the sport, Tour organisers have applauded the weeding out of drugs cheats. They see it as a positive step which will, they hope, deter others. Pleitgen, who helps to negotiate television rights deals for the Olympic Games and World Cup, said he hoped that both parties - ARD/ZDF and the race organisers - would "come to a common agreement without having to go through the courts."
He added that a pullout by ARD would "make it more difficult" to obtain such rights in the future because "the confidence would no longer be there."
The Tour de France is one of the most popular televised sports events in Germany and Pleitgen said breaking the contract "would be hard to defend to the German people who pay their television licence fees."