Bruni made the announcement on Thursday (20Oct11) as part of a thank you tweet to fans.
She wrote, ""I'm deeply touched by all your messages since the birth of our little Giulia. In this happy time, my husband and I would like to thank those of you who showed us so much kindness.""
The little girl was born in Paris on Wednesday night (19Oct11). She's the first child for the couple, who wed in 2008.
The French leader has three kids from his two previous marriages, while Italian beauty Bruni is mother to 10-year-old Aurelian.