Europe-wide protests to 'save the internet' have been called on Saturday ahead of an EU vote next week which could overhaul web copyright laws.
The proposed changes would force Google and other online platforms to sign licensing agreements with musicians, performers, authors, and journalists so they can use their work.
The European Parliament will vote on Tuesday on whether it wants to approve a proposal started by the European Commission two years ago to protect the bloc's cultural heritage and ensure publishers and artists get fair compensation from web giants like YouTube.
But Google and internet activists have taken issue at the potential copyright filters and say it could pose a threat to the free exchange of opinions and culture online.
Article 13 of the copyright directive could mean sharing platforms such as the likes of Google, YouTube, and Facebook's Instagram would have to take more responsibility for copyrighted material being shared illegally on their platforms.
That means they would be liable if their users upload or publish unlicensed content, such as photos, videos, source code or music, on their website. Such actions would require a licence fee to be paid, or for the content to be pre-filtered or automatically censored.
Critics say the filters are expensive and could lead to mistaken blocking. The campaign platform, Save the Internet, which called for Saturday's protests, said such filters would "block legal expressions of opinion and creative content, as automatic systems cannot accurately distinguish legitimate uses from copyright infringements".
The group, which has received about five million signatures for its online petition, also argues the filters would not just tackle large companies, but smaller platforms too.
Wikipedia meanwhile has said the EU rules would police all platforms, which could harm free expression.
Some EU countries have also voiced concern. Last month, Finland, Italy, Luxembourg, the Netherlands and Poland refused to support the internet reforms.
But artists have voiced their support for the online overhaul.
Film director Pedro Almodovar and Abba's Benny Andersson are among some of those who favour Article 13.
Writing in The Guardian, Debbie Harry, the lead singer of Blondie said the law would "significantly improve the ability of the creative community to secure fair deals for the use of their work by user-uploaded content services such as YouTube."
Harry added that companies such as Google and YouTube "have used their financial power and reach" to lobby a law that would "secure" musicians' futures.
The online group Europe for Creators, argues platforms such as YouTube can at the moment "pretty much do whatever it wants" but if Article 13 became law, "a wider variety of artists will be able to monetise the use of their work" as platforms like YouTube will have to negotiate licensing deals with authors and creators.