The thief simply walked into the gallery and helped himself to the statue of a mother and child by the Colombian artist Fernando Botero.
He then coolly walked unchallenged down one of the most closely guarded streets in France, home to the British and Japanese embassies as well as French President Emmanuel Macron's official residence, the Elysee palace.
Security around the Elysee has been heightened as a part of France's state of emergency after the country was hit by a series of terror attacks over last two years.
The gallery is also almost opposite the interior ministry, which is in charge of security and the police.
According security camera footage, the bearded thief caressed the 10-kilo (22-pound) statue of typically fleshy Botero figures, then looked around him before taking the statue from its plinth and discreetly making an exit.
No alarms were set off.
Staff at the Bartoux gallery only realised it was gone when the gallery closed on Saturday evening, police said.
Botero, 85, is Latin America's best known living artist, and is renowned for his slightly surreal and often comic fat figures, which have made his paintings hugely popular across the globe.
The stolen sculpture, which is worth at least 425,000 euros ($491,000), is one of eight made by the artist, all of different sizes.
Botero, who divides his time between Paris and Italy, could not be contacted.
"It's really a nightmare, we hope to get it back" staff at the gallery told French media.