Polish Prime Minister Donald Tusk said his government would sign the Anti-Counterfeiting Trade Agreement that seeks to establish international standards to enforce intellectual property rights.
Critics of the agreement argue it could curb freedom of expression, and government Web sites have been hacked in protest, the BBC reported.
Protest marches were held in several cities across Poland Wednesday with young people holding banners reading "no to censorship" and "a free Internet."
The agreement has already been signed by the United States, Australia, Canada, Japan, Morocco, New Zealand, Singapore and South Korea.
It shares similarities with the Stop Online Piracy Act shelved by the U.S. Congress after a backlash of Web protests that included sites being blacked out or partially obscured.