Users looking for information on the German-language version of Wikipedia were met with black screens on Thursday.
The online encyclopedia went offline for the day to protest the planned changes to the European Union's copyright laws.
A statement on the German Wikipedia site said that the legal changes "could lead to a considerable restriction of the free internet" and that they could "considerably impair freedom of expression, artistic freedom and freedom of the press."
John Weitzmann, the legal head at the Wikimedia association, defended the decision to temporarily shut down the site, saying that he hopes it will spur change.
"It's the most drastic means we have available in order to draw attention to something," Weitzmann told German radio station Bayern 2.
He added that he hopes the reforms can still be amended as they could pose serious problems for Wikipedia and other noncommercial websites.
The European Parliament is due to adopt the reforms next Tuesday.
Protests over planned changes
The planned changes, which were agreed in September, seek to update the EU's two-decade-old copyright law for the digital era.
Numerous groups have taken issue, however, with the proposed changes — particularly with Article 11 and Article 13.
Article 11 would force Google and other platforms to pay media publishers for displaying snippets of news. Article 13 would make platforms legally liable for copyrighted material uploaded by users.
The EU has said the changes are a way to ensure producers of content, including the news, music and film industries, are paid fairly for the material they post online.
Activists have warned that the changes would force online platforms to install automatic upload filters that would screen user-uploaded content for copyright infringement — and could excessively block content as a result.
The proposed new law has drawn criticism from Internet giants like Google and Facebook but also from librarians, journalists and activists. Over 3,000 people took part in a protest in Berlin in early March against the EU's copyright plans.
rs/sms (AFP, dpa)