Now, Bruni-Sarkozy is about to have a baby, and the pending birth has taken on the air of a state secret - revealing the caution within Sarkozy's political team as the unpopular president eyes a possible re-election bid.
Bruni-Sarkozy is poised to become the first first lady in modern France to give birth. Sarkozy, who has long cast himself a mold-breaker, is the first French leader to divorce - and remarry - while in office. They wed in early 2008, 3-1/2 months after he divorced the now-former Cecilia Sarkozy.
The hush-hush atmosphere over the upcoming birth says a lot about France.
France's media establishment has a reputation for cushy ties to political powers-that-be, whose personal lives have mostly been off-limits. And conventional wisdom holds that the French public, in almost conscious contrast to what is considered Anglo-Saxon fascination with politicians' private lives, doesn't care much anyway.
The expectant mother, 43, said in recent media interviews that she didn't know the baby's gender and will make no photos of the baby public, praising a French law that bans the publication of images of children without parental consent.
The Elysee Palace has never officially acknowledged that a baby is on the way, and has indicated it won't announce the birth. Sarkozy's younger brother, doctor-turned-businessman Francois Sarkozy, told The AP that the family is leaving it up to the parents themselves to decide when and whether to say anything.
One unresolved question is how much the infant, even if it isn't seen, could provide a boost to Sarkozy, whose poll numbers are bleak as presidential elections loom six months away.
Bruni-Sarkozy, speaking to the BBC last month, insisted that the French were "uninterested" in her pregnancy. But some speculate that a newborn in the Elysee could help soften Sarkozy's rough-edge image: He made his name as a law-and-order interior minister and is seen as increasingly out of touch with the day-to-day problems of ordinary voters.
Yves Derai, a publisher and co-author of the recent book "Carla et les Ambitieux" (Carla and the Ambitious), says the president should play the communication about the birth carefully, "because the French blame Nicolas Sarkozy for looking after himself a lot - and not enough after them."
And in the run-up to the election, timing is everything.
"If this had happened at the beginning of his term, we would have had violins playing, photos in Paris-Match (magazine), happiness in the whole family, etc. But now, I think they're going to play low profile," Derai said.
The president, 56, has three sons from his two previous marriages. Though French media never mention it, he's already a grandfather: The wife of his second son gave birth last January. The president wasn't shy about that baby's arrival, announcing the child's name himself.
Sarkozy gambled a bit in recent days by traveling to the Caucasus Mountains and Germany for his duties of state.
Le Parisien newspaper reported Sunday that Sarkozy, in a meeting with President Ilham Aliyev in Azerbaijan's capital last week, said: "My wife would have liked to come to Baku, but it would have surprised people if our child were born here!"
Sarkozy's father, Pal, announced the pregnancy in May to German daily Bild and later told the newspaper the due date: Oct. 3. Gossip magazine Closer said officials were keeping quiet because Bruni-Sarkozy's age makes it a higher-risk pregnancy.
As of Monday, friends of the family said the first lady was still expecting. "I can tell you she spent a nice weekend at the Elysee" and was still pregnant, said Patrick Balkany, a longtime Sarkozy friend and political ally.
The glamorous Bruni-Sarkozy first showed signs of a midriff bulge while standing alongside other first ladies at the G-8 summit in Normandy in May.
Her husband has been coy, quiet and even cheeky about the pregnancy.
At a news conference at that summit, after an Italian journalist offered her congratulations, the president coyly replied: "I congratulate you too for being Italian, which is a country we like so much in France." (Bruni-Sarkozy was born Italian.) He didn't answer the journalist's question: whether he knew if it was a boy or a girl.
Plainclothes police are patrolling outside a western Paris maternity clinic where rumors hold Bruni-Sarkozy is to give birth.
Bruni-Sarkozy, who became French after she married Sarkozy, made her name as a supermodel on catwalks worldwide - under the rapid-fire flashes of photographers' cameras. She clearly wants to spare her two children from the glare.
Bruni-Sarkozy says she made a mistake by taking along her young son from a previous relationship on a much-photographed holiday in Jordan with Sarkozy during their courtship in late 2007. In eerie TV images, the boy put his face in his hands while riding on Sarkozy's shoulders.
France is no stranger to secrecy about its first families. President Francois Mitterrand kept quiet about a daughter he had fathered out of wedlock in 1976, five years before he took office. The daughter, Mazarine Pingeot-Mitterrand, emerged in public only at his funeral in 1995.
"You don't have a child for the gallery," Bruni-Sarkozy told French TV network TF1 recently. "I will do everything to protect this child... I will not show photos of this child, I will never expose this child."