The statement by the French presidency said "Cecilia and Nicolas Sarkozy announce their separation by mutual consent. They will make absolutely no comment."
Rumors have been swirling for weeks that France's 52-year-old president and his glamorous, 49-year-old wife were about to split.
On Wednesday, France's news magazine reported on its website that the first couple had appeared before a judge to begin divorce proceedings.
Cecilia Sarkozy was considered her husband's "right-hand-woman" when Mr. Sarkozy was the country's interior minister. She even had an office in the ministry.
But she played a low-key role during the presidential campaign and as presidential spouse. Although she flew to Libya to secure the release of Bulgarian health workers sentenced to death there, she was conspicuously absent on a number of key occasions, including a barbecue in Maine hosted by President George Bush.
While first ladies traditionally accompany their husbands on official trips and sometimes embrace social causes, French constitutional analyst Didier Moss says he does not believe the split will hamper Mr. Sarkozy's ability to carry out his presidential duties.
Speaking on a French radio station, Moss said presidential protocol does not oblige a French leader to be married or accompanied by someone. He said the president's marital woes only involve two people: Mr. Sarkozy and his wife.