Deutsche Telekom filed a legal case against controversial rules set to be imposed on operators in Germany’s 5G auction, following similar action from local units of Telefonica and Vodafone, Die Welt reported.

According to news outlets in the country, Deutsche Telekom’s suit was filed in Cologne and means all three operators have opened legal proceedings against regulator Bundesnetzagentur’s divisive 5G auction terms, which were finalised in early December.

Actions by Telefonica Germany and Vodafone Germany were reportedly submitted in the penultimate week of December.

The cases come as little surprise as industry group GSMA and all three operators have been hugely critical about the auction rules since proposed conditions were outlined while the document was still at the draft phase. At the time, Vodafone Germany threatened to take legal action should they be approved.

Assuming the conditions outlined by the regulator stand, 5G spectrum will be allocated alongside coverage commitments described by GSMA as “unrealistic”, with the industry body adding it put Germany’s 5G future at risk.

Despite the ire of industry, following the publication of the auction rules some politicians in Germany reportedly demanded even stricter terms for the allocation of 5G-suitable spectrum.

The auction is scheduled for Spring 2019, though it is unclear if the legal action will have any impact on this timeline.