Lebel said it was the first time in the history of the French republic that a president had married while in office.
Sarkozy and Bruni, a singer and former model, reportedly met in November, soon after his divorce from his second wife Cecilia, in October.
The pair went public with their relationship during a visit to Disneyland Paris, and they remained in the spotlight during trips to Egypt and Jordan.
Sarkozy's openness about his private life has surprised many French who are accustomed to presidents who are private about their partners.
The president told a press conference last month that his relationship with Bruni was serious and all but confirmed that he planned to marry her.