The works are believed to have started to appear as early as last Wednesday, U.N.-designated World Refugee Day, and some have already been vandalised.
One mural, on a street in northern Paris where migrants sleep rough, shows a black girl spraying a pink wallpaper pattern over a swastika. The painting was subsequently defaced to make it look like she was painting the Nazi symbol herself.
Others carry signature traits of the British artist, such as a rat familiar in his other works, in this case flying through the air on the cork from a champagne bottle.
A PR agent who has worked for Banksy in the past did not respond to a request for comment.
Banksy, whose real identity is unknown, is famous for outdoor graffiti, including on Israel’s barrier at the West Bank and Disneyland where he painted a life-size figure of a Guantanamo Bay detainee.
Once a small-time graffiti artist from the English town of Bristol, Banksy’s work has become hugely valuable. French authorities placed a protective cover over his painting of Apple founder Steve Jobs as a refugee on a wall at a migrant camp in Calais in 2015.