Updated at 1:02 p.m. Eastern
French first lady and former model Carla Bruni-Sarkozy is quoted in a new book as saying that Michelle Obama told her life as a president's wife was "hell," according to the British tabloid Daily Mail.
But the White House and the French government .
The book, "Carla and the Ambitious" claims Bruni-Sarkozy asked Mrs. Obama what life was like for her since her husband, Barack Obama, won the U.S. presidency.
"Don't ask. It's hell. I can't stand it," Mrs. Obama is reported as saying.
A spokesperson for Mrs. Obama flatly denied the quote.
"The First Lady never said that," Katie McCormick-Lelyveld said.
A spokesman for France's embassy in Washington, D.C., also said Thursday that the comment was never made and said Sarkozy-Bruni had nothing to do with the book's publication.
"Mrs. Bruni-Sarkozy distances herself completely from the content of the book 'Carla and the Ambitious,' which was not authorized and the authors alone are responsible for its contents," says Emmanuel Lenain, the embassy spokesman. "The words attributed to the First Lady of the United States were never said."
The Daily Mail reported that "Carla and the Ambitious," by Michael Darmon and Yves Derai, was written "in collaboration with Miss Bruni."
The book says the exchange occurred during a visit to the White House by the French first couple last March.
Meanwhile, the author of another book, "Carla: A Secret Life" -- an unauthorized biography chronicling Bruni-Sarkozy's transformation from an allegedly tempestuous man-eater into an apparent meek, model spouse -- suggests she has become something of a political liability for her husband.
Author Besma Lahouri, who interviewed more than 100 people who have known the French first lady, but not Bruni-Sarkozy herself, said the former model's alleged rivalry with Michelle Obama has strained relations between the French and U.S. presidential couples, and Bruni-Sarkozy's image of distant, well-heeled perfection has kept her at arm's length from the French people.
© 2010 CBS Interactive Inc. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. The Associated Press contributed to this report.