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 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 that we have available to in order to draw awareness 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 non-commercial websites.
The European Parliament is due to adopt the reforms next Tuesday.