Yes. Any party affected by a DNS block set up according to the two-step procedure can apply to the courts to have this block reviewed. This means German internet access providers, operators of the structurally copyright-infringing websites or internet users in Germany who believe that the DNS-block does not meet the legal requirements. Copyright holders can appeal to the courts if a DNS-block was rejected by the CUII review procedure.
In its decision in UPC Telekabel (Case C-314/12, para. 56), the Court of Justice of the European Union (CJEU) stated that internet users should be able to assert their rights in court after the blocking measures taken by a provider have become known. According to the German Federal Court of Justice (Bundesgerichtshof – BGH), it is sufficient that internet users can assert their rights against the internet access provider in court on the basis of the contractual relationship existing between them (German BGH judgment of 26 November 2015 - I ZR 174/14). Internet users are entitled to recourse to the complaint mechanism prescribed by the courts if they are of the opinion that the DNS-blocks set up via the CUII procedure do not comply with the legal requirements despite the careful two-stage examination.
The CUII's two-step review procedure seeks to avoid unnecessary court proceedings in clear cases of mass copyright infringement. The two-stage examination procedure, with preliminary examination by the competently staffed CUII review committees and a state follow-up examination by the German Federal Network Agency for Electricity, Gas, Telecommunications, Post and Railways (Bundesnetzagentur – BNetzA), can achieve this. The legal provisions for DNS blocking of structurally copyright-infringing websites do not mandate a prior decision by a judge. A court review nevertheless remains possible for all affected parties.