But the supermodel-turned-musician greeted well-wishers in person during a special day at the Elysee Palace.
Carla, 43, had dressed her bump in an elegant dress under a black coat for Patrimony Day when France's most treasured heritage buildings are open to the public.
On a public engagement a few days previously, she admitted to onlookers: "I've had enough".
"I have to lie down or sit down most of the time," Carla went on, reports French publication Le Parisienne. "Of course, drinking or smoking is out.
"I'm anxious for it to be over. It could happen any time from October 1. Besides, Aurelien came before full term".
Aurelien is her 10-year-old son from a previous relationship. Her husband has three sons, Pierre, Jean and Louis from two previous marriages.
And indeed, although she made an effort to appear upbeat while shaking hands and chatting with members of the public, Carla did look tired.
The president and his wife usually travel to New York in the autumn, but this time she will stay behind.
In pictures: Carla, the model wife