The DFB are to investigate how Eintracht Frankfurt were not given a penalty in their 1-0 defeat to Augsburg on Sunda
Hannover piled the pressure on their former coach Mirko Slomka with a 2-0 victory over his Hamburg.
Augsburg picked up their first win of the season by beating Eintracht Frankfurt 1-0.
Borussia Dortmund earned a 3-2 win at Augsburg on Friday night, although they nearly let the points slip in Bavaria.
Bayer Leverkusen claimed a shock 2-0 Bundesliga win at Borussia Dortmund on Saturday, while Hannover beat Schalke.
Hoffenheim began their Bundesliga campaign with a 2-0 win over Augsburg on Saturday afternoon.