Nikolas Sarkozy is the leader of the ruling right-of-center party UMP and the former interior minister who stepped down in March to focus on his presidential bid in the upcoming election.
"If you want to know which one is closer to me - the U.S. or Russia, which we saw in action in Chechnya - I will say the U.S.," the candidate said.
During its two military campaigns against a separatist regime in the North Caucasus republic of Chechnya in the mid-1990s through the early 2000s, Russia faced widespread international criticism for alleged human rights violations committed against Chechen civilians.
Sarkozy said France must develop friendly relations with the U.S., but at the same time must be free to level criticism against the country when needed.
"I tell great powers, including the U.S., that they are mistaken because they have not signed the Kyoto Protocol and that they are wrong in Iraq. But we have common values, such as democracy," Sarkozy said.
Opinion polls have given Sarkozy 27% of the votes. He is followed by Socialist Party candidate Segolene Royal, with 23% of the votes, and Francois Bayrou from the centrist Union for French Democracy with 19%.
The first round has been scheduled for April 22 and the second for May 6 if there is no outright winner.