In his first major speech as president on France's nuclear "strike force," Sarkozy said atomic weapons would remain a vital component of its defenses to deter potential attackers.
"It is the nation's life insurance policy," he said.
Sarkozy said that while France faces no foreseeable danger of invasion, other threats exist. He singled out Iran's expansion and improvement of its long-range missile forces amid what he called "grave suspicions" about whether the Iranians are trying to develop atomic weapons.
"The security of Europe is at stake," he said.
Sarkozy did not say how many warheads France currently has, and the Defense Ministry said that information is a state secret. The Federation of American Scientists, which tracks nuclear arsenals around the globe, said in a status report for 2008 that France had 348 warheads.
More than half of France's nuclear weapons are believed to aboard submarines, with the rest on warplanes.
Sarkozy said France would cut reduce its airborne force of atomic weapons by a third. "After this reduction, our arsenal will include less than 300 nuclear warheads," he said.
Speaking to workers finishing a new nuclear submarine, The Terrible, Sarkozy followed his announcement of weapons cuts with appeals for other nations to scale back their nuclear facilities.
He appealed to China and the United States to ratify a nuclear test ban treaty that they signed in 1996. "It's time to ratify," he said.
Sarkozy also called for negotiations on treaties to ban short- and intermediate-range nuclear-armed missiles and bar the manufacture of fissile material for new atomic weapons.
Russia welcomed the idea, saying it was similar to a call made by President Vladimir Putin in October. "We welcome proposals aimed at strengthening internatioanl security," a Foreign Ministry spokesman said, according to Russian news agencies.
Since Sarkozy is France's first leader born after World War II, his underlining of the need for nuclear weapons, despite budget difficulties, was significant in reaffirming the defense policy would continue despite the generational shift in political leadership.
Donning his commander-in-chief cap also was part of an effort by Sarkozy to appear more presidential. Following a divorce in office, a subsequent quick marriage to a former model and outbursts of temper, Sarkozy has faced criticism his behavior is unbecoming for a head of state.
The Terrible is the fourth vessel in France's new generation of nuclear-powered submarines that carry underwater-launched missiles with atomic warheads. Quieter than predecessors, The Terrible is scheduled to enter service in 2010 and be armed with the new M51 missile with multiple warheads and a longer range.
France's airborne nuclear weapons are carried by three air force squadrons using the Mirage 2000N and a navy flotilla of upgraded Super Etendard jets. All four forces are set to get new, high-tech Rafale jets.
Bruno Tertrais, an expert on nuclear deterrence, said Sarkozy's nuclear policy was largely a continuation of his predecessor in the presidency, Jacques Chirac, but Chirac was not so open about the number of warheads in the French arsenal.
"Chirac did not believe that transparency was worthwhile or interesting," said Tertrais, a senior research fellow at the Foundation for Strategic Research think tank. "There is more continuity than change, but the level of transparency now is something new."