The protest took place on the Sunday evening.
"We have another freedom movement to take part in. To free India from the real 'tukde tukde' gang dividing Ind on the basis of identity," tweeted Congress Rajya Sabha member Rajeev Gowda.
The former Indian Institute of Management-Bangalore (IIM-B) professor called on the protesters to take a pledge to fight for an inclusive India and celebrate diversity.
"I urge everyone to join the struggle to save the soul of our country," Gowda said as he participated in the demonstration at the Townhall in Bengaluru.
A huge flexi poster was hung to the columns of the Acropolis-styled Townhall facade with the inscription 'India Against CAA' and the preamble of the Constitution of India juxtaposed.
The protesters waved the Karnataka state flag, Indian flag and placards as they sloganeered against the new law offering selective citizenship to the persecuted Christ, Hindus, Sikhs, Jains and Zoroastr from Afghanistan, Pakistan and Bangladesh, excluding all kinds of persecuted Muslims.
Muslim minority sects such as Shias, Ahmadiyas and others are persecuted in Afghanistan, Pakistan and Bangladesh.
A placard at the Townhall read: "Stop attack on the Indian Constitution. #AgainstCAA."
Another protester waved a caricature poster equalising Prime Minister Narendra Modi to the Holocaust perpetrator and former German Chancellor Adolf Hitler.
Making his presence felt at the protest, historian Ramachandra Guha said India was founded on the principles of diversity.
"We want democracy, we want pluralism," Guha said.
Sowmya Reddy, Karnataka Legislative Assembly member from Jayanagara spoke at the CAA protest demonstration.
She said: "A revolution has begun! We will not let India's diversity die. Thanks to all the organisers. Wake up."
Many members of the Muslim community also took part in the protest on Sunday.
Earlier on Friday, thousands of Muslims protested across Karnataka after Friday prayers and presented memoranda against the CAA to government officials.
On Saturday, hundreds of Assamese and people from other Northeast states, working and living in Bengaluru, protested against the CAA at the Townhall.
( With inputs from IANS )