In early 2005, German football was overshadowed by the discovery of a €2 million match fixing scandal centered on second division referee Robert Hoyzer, who confessed to fixing and betting on matches in the 2. Bundesliga, the DFB-Pokal (German Cup), and the then third division Regionalliga. The scandal has been described as the largest controversy in German football since the Bundesliga scandal of the early 1970s, as numerous players, coaches and officials have been accused of involvement with an organised crime group in the scheme, which came on the eve of Germany playing host to the 2006 World Cup.
 Although it does not appear that any Bundesliga games were involved, the matches in question do include a DFB Cup first-round contest between regional side SC Paderborn and Bundesliga heavyweights Hamburger SV played on 21 August 2004. Hamburg lost 2–4 as two highly questionable penalties were awarded to Paderborn and Hamburg footballer Émile Mpenza was sent off for protesting as the club was eliminated from the lucrative competition.
 Four referees – Lutz Michael Fröhlich, Olaf Blumenstein, Manuel Gräfe, and Felix Zwayer – went to officials of the German Football Association (Deutscher Fußball-Bund, DFB) with their suspicions about Hoyzer. Initially, the DFB did not immediately act, but after becoming aware of the accusations, Hoyzer stepped down from his role as a referee.
 Indications are that Hoyzer had regular meetings in Berlin with a group of three brothers who were part of a Croatian gambling syndicate connected to an organized crime group. After a confession from Hoyzer, several suspects were put under surveillance and on 28 January 2005 a number of people were arrested. Milan Šapina, operator of the Café King sports betting agency and his brother Philip were taken into custody, along with Hertha BSC players Alexander Madlung, Nando Rafael and Josip Šimunić. Madlung, Rafael, and Šimunić all played in Hertha's surprising 3–2 defeat to third-division side Eintracht Braunschweig in their 22 September 2004 German Cup match, with Madlung giving up a crucial 80th minute own goal, only four minutes after coming on as a substitute. The trio came under suspicion for having been known to associate with the Šapina brothers, but there has been no proof that they actually participated in the manipulation of this or any other match.
 As witnesses against Hoyzer, the Berlin referees Lutz Michael Fröhlich and Manuel Gräfe were immediately relieved of their officiating responsibilities for their own safety, being replaced by Franz-Xaver Wack and Torsten Kinhöfer. The referees scheduled to officiate matches in the 19th round of Bundesliga play on 29 and 30 January 2005 were all changed the day before the games were played.
 Hoyzer co-operated with investigators in helping to uncover the details of the scheme, implicating other officials, players, and a group of Croatian-based gamblers. This led to an investigation by the league, as well as a criminal investigation. By the end of 2005, it appeared that the scandal did not directly involve the Bundesliga and was confined to lower divisions. The investigations lead to the following results:
 The DFB-Kontrollausschuss (DFB Committee of Control) reacted to the scandal with a number of measures intended to prevent similar incidents in the future:
 These measures are regarded as an immediate first step taken to manage the problem of match-fixing. Other more detailed proposals will be put forward by an expert committee appointed to address the issue. On 13 February 2005, the DFB announced the Ausschuss für das Problem Spielmanipulationen (Commission for the Problem of Match Manipulation) as being made up of DFB President Zwanziger, DFL President Hackmann, Treasurer Schmidhuber, and Secretary General Horst Schmidt.
 The DFL is also considering a departure from tradition by employing professional officials in place of the amateurs now used. DFL President Werner Hackmann sees the controversial step as possible in light of the recent scandal. The former chairman of the board of Hamburger SV feels that the use of full-time referees earning a good wage could help deflect bribery attempts in the future. Former star player and head of Germany's 2006 FIFA World Cup Organizing Committee Franz Beckenbauer expressed opposition to the idea of employing professional officials feeling that the current system has worked quite well and is solidly supported by the excellent training program run by the DFB. The former FIFA referee Hellmut Krug, DFB Director of Officials (Schiedsrichterabteilung) criticized the control system the DFB had in place because it had been known for some time that Hoyzer was making dubious decisions, but there was no action taken. He also emphasized the more general need for observers to prepare written match reports as is the practise for all Bundesliga matches.
 There was some fear that the scandal affecting the largest football association in the world could have some negative impact on the upcoming World Cup to be hosted by Germany in 2006. While World Cup Organising Committee chief Franz Beckenbauer expressed his concern, government spokesman Thomas Steg acknowledged the efforts of the DFB in acting in a committed manner in quickly dealing with the issue. A spokesman for Germany's Ministry of the Interior warned against an atmosphere of general suspicion and exaggerated mistrust given what appeared to be, on investigation, the narrow scope of the problem. It was felt that the response to the scandal by the DFB demonstrated the general effectiveness of the sport's governing institutions. 
Interior Minister Otto Schily also encouraged all game officials to support the DFB and public prosecutor's office in quickly addressing any suspicions raised. He indicated that it was clear that the vast majority of officials conduct themselves in an honest and professional manner and that to be generally suspicious of the game's officials without cause would be unfair.
 The scandal attracted international media attention, but DFB and FIFA worked aggressively to ensure that the controversy died down before the 2006 World Cup.
 In the course of the investigation by the DFB a number of matches were examined to determine if there was an attempt to manipulate them and if any such attempt had affected the outcome. The matches and their relevant detail are listed below in chronological order. The DFB set a cut off date of 30 June 2005 for filing protests over matches that may have been subject to attempted manipulation. While Hoyzer had drawn the suspicion of a number of his fellow officials sometime earlier, it was the 21 August 2004 match between SC Paderborn 07 and Hamburger SV that precipitated the complaint to the DFB against him.