In an interview with NBC television, Bruni, who has rejuvenated her singing career since her husband was ousted from the Elysée Palace last year, was asked whether Sarkozy changed the nappies of their baby Giulia.
"He is a Latin man, so he does not do these kind of things," Bruni said.
Realizing she might be in a spot of bother when she gets home, Bruni then said: "But he's a great father. He has three boys and he is a grandfather. We love our daughter."
Bruni was in the US to promote her latest album 'Little French Songs', which includes the track 'Mon Raymond' in which she compares Sarkozy to a pirate.
"I just wanted to show that even if he wears a suit and tie and he has a very serious job he went to work early in the morning, he could be like a pirate."
It remains to be seen whether the revelation that Sarkozy does not change nappies may harm his chances of making a comeback at the 2017 presidential election.
Earlier this year, he fueled speculation that a dramatic comeback could be on the cards, saying in an interview that he may have no choice but to run for President in 2017, for the sake of France.
However, he was then charged with abusing his position to take financial advantage of Liliane Bettencourt.