Thousands of protesters marched through Berlin on Saturday against the EU's planned copyright reforms that will likely see the introduction of automatic upload filters by the likes of Facebook and YouTube.

Organizers said around 3,500 people took part in the demonstration from the trendy Kreuzberg district to the European Commission representative's office at the Brandenburg Gate.

Article 13 will "have massive ramifications for freedom of expression and the diversity of the internet," the protest alliance "Berlin gegen 13" (Berlin against 13) wrote on its website.

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The proposals will see social media platforms become liable if they publish content that infringes copyright, including images, video or music.

Bots can't decide

User-generated material will need to be checked before it is published, and the only economic way of doing this is through the introduction of automatic filters, activists have warned.

The filters, which would sift out content that breaches copyright laws, would be too restrictive, they say.

Read more: Opinion: EU online copyright reform won't break the internet

One of the protest banners read: "This protest can't be displayed for copyright reasons"

Volker Grassmuck, a spokesman for the Digitale Gesellschaft (Digital Society) group, warned that news content could also be filtered if platforms fear legal action by those implicated in scandals.

He said whistleblowers, who upload private material to uncover serious cases of wrongdoing, would also be affected, leading to a decline in the diversity of opinion online.

The European Commission argues that existing laws need to be amended to bring them up to date for the digital era and allow creative artists protection online.

Concerns 'overstated'

Gerhard Pfennig, a spokesman for Germany's Initiative Urheberrecht (Copyright Initiative), said criticism of the filtering system had been exaggerated.

He told public broadcaster Rundfunk Berlin-Brandenburg (RBB) that filtering would only be necessary for content not already covered by copyright contracts with agencies that collect royalties on behalf of rights holders.

He hit out at the "myth of uncontrolled filters as if a fence were being erected online," when "the aim of this directive is exactly the opposite."

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