It's been an historic week for German football on the pitch as Bayer Leverkusen won the Bundesliga for the first time and both Borussia Dortmund and Bayern Munich progressed to the semifinals of the Champions League.

But it's also a big week off the pitch as the German Football League (DFL), which operates the Bundesliga, opens the bidding for the sale of its domestic broadcast rights for the seasons 2025/26 to 2028/29.

The billion-euro negotiations take place every four years and are a vital process since they concern German football clubs' most important revenue stream.

However, the DFL confirmed on Wednesday evening that it had taken the unprecedented step of suspending the auction after just three days following a legal complaint from one of the bidders, current rights holder DAZN.

What exactly has DAZN complained about?

According to German media reports, the online streaming service has complained of unfair treatment by the DFL, accusing the league of "abusing its dominant position in the football broadcast rights market" and "contravening German and European competition law."

In a letter to the DFL seen by the mass daily BILD and the regional Frankfurter Rundschau newspaper, DAZN expressed "deep disappointment and great dismay that our offer was rejected, even though [we] had made the most financially attractive and most convincing offer for rights package B."

"We are led to believe that our financial offer lay substantially above every other offer."

Rights package B is the largest package on sale, according the winning bidder the rights to exclusively broadcast 196 live games per season, including the five 3:30 p.m. kickoffs every Saturday, the weekly Friday night fixtures and the end-of-season relegation/promotion play-offs.

DAZN, which in the current broadcast deal has the rights to the Friday and Sunday fixtures, making it the DFL's second-biggest broadcast partner, says it had bid for the package against pay TV broadcaster Sky, the premier partner which currently holds the rights to all Saturday matches.

Claiming to have lost out due to a failure to produce a last-minute bank guarantee rather than a private letter of responsibility which it said had sufficed in previous auctions, DAZN complained: "We have no other explanation for this behavior other than that the DFL management had already anticipated awarding package B to its preferred bidder."

DFL rebukes 'incorrect and unfounded' accusations

The DFL confirmed the reports to the German SID sports news agency on Wednesday night but strongly rejected the accusations.

"The insinuations and accusations raised are incorrect and unfounded and we reject them in the strongest possible terms," it said in a statement, claiming that the DAZN letter of complaint contains "numerous incorrect portrayals and misrepresentation of facts."

The DFL said it would discuss the issue with Germany's Federal Competition Regulator, the Bundeskartellamt, which has already been alerted by DAZN.

It insisted that it is conducting the auction process in adherence to all relevant rules and regulations and "in a transparent and non-discriminatory manner," but that chief executives Marc Lenz and Steffen Merkel had decided to temporarily halt the auction "in order to protect the legal security of the process."

Bundesliga TV rights: What now?

The legal dispute comes at a highly inopportune time for the DFL, whose current domestic broadcast deals with Sky and DAZN run out at the end of next season.

The current deals are worth around €1.1 billion ($1.17 billion), a sum which is divided up among Bundesliga clubs according to a points-based formula.

By way of comparison, the equivalent deal for England's Premier League is worth £1,63 billion (€1.9 billion; $2 billion).

The DFL will be especially keen to increase that figure following the recent collapse of a proposed private equity investment in its international broadcast rights after large-scale fan protests.

But it now faces the prospect of weeks or months of potential legal wrangling.

Edited by: Wesley Dockery