The stencil had been on display near the Pompidou Centre in central Paris, where it was protected by a Plexiglass shield, but now it has disappeared.
The image of a masked rat holding a knife was painted on the back of a traffic sign in Paris' 4th arrondissement.
Local police confirmed that it had gone missing some time overnight on Sunday, and an investigation is underway.
— Print Them All (@PrintThemAll) June 27, 2018
Banksy, who keeps his identity a closely guarded secret, rarely confirms whether he is behind works of street art, but he had shared an image of the Paris sketch on his Instagram feed back in 2018.
It is not the first of his artworks to be stolen in Paris, earlier this year a painting in homage to terror victims of the 2015 attack was stolen from the Bataclan concert hall in Paris, where 90 people were killed in a jihadist attack.