Armstrong and Contador worked together as Astana teammates during this year's Tour de France, and the Spaniard won the Tour for a second time while Armstrong finished third.
Armstrong has since left the Kazakh-funded team to launch his own outfit, RadioShack, which has yet to be granted a ProTour license.
Andy Schleck of Luxembourg, who finished second behind Contador in July, and sprinting ace Mark Cavendish of Britain are also expected at the Paris ceremony.
The 2010 Tour will start from Rotterdam, Netherlands, on July 3 with a final stage in Paris on July 25. In between, riders are expected to celebrate the first crossing of the Pyrenees 100 years ago with as many as four stages in the daunting mountains that border France and Spain.
Armstrong skipped the 2009 Tour route presentation after race organizers gave him a cool reception upon his return to cycling after three years in retirement. Jean-Etienne Amaury, president of Amaury Sports Organization, which runs the Tour, said Armstrong's comeback was an embarrassment for cycling.
But Armstrong was cheered all the way this year, a marked turnaround from previous years when his cycling feats were often greeted by skepticism and accusations of doping _ which he has always denied.
In 1910, Tour riders for the first time climbed the four legendary Pyrenean passes _ Peyresourde, Aspin, Tourmalet and Aubisque. According to La Depeche du Midi newspaper, there is a strong possibility that the Tourmalet, one of the toughest climbs in cycling, will be scaled twice next July.
One stage in the Pyrenees could see the pack go through Peyresourde, Aspin, Aubisque and Tourmalet on the same day for the first time since 1969. That year, Belgian great and five-time Tour winner Eddy Merckx won the stage in Mourenx after a sensational breakaway.
International Cycling Union president Pat McQuaid is also expected in Paris despite a new feud with the French anti-doping agency, known as AFLD. McQuaid promised last week to keep up the "endless fight" against doping. But he has been accused by AFLD president Pierre Bordry of giving favorable treatment to Astana, with the team receiving advance notice of drug tests during the Tour.
The UCI responded by saying it "scrupulously respects the obligations imposed by the World Anti-Doping Code" and that "the equal treatment of teams and riders is strictly guaranteed."
The two organizations have had a tense relationship in recent years, with the AFLD accusing the UCI of not taking a tough enough stance against doping.