Carlo Ancelotti has been asked to explain himself by the German Football Association (DFB) after making an offensive gesture to a home supporter at Saturday's 1-1 draw against Hertha Berlin.
The Bayern Munich head coach appeared to raise his middle finger as he left the pitch after the match and told ARD immediately afterwards he had done so "because I was spat on".
Having initially reviewed the incident, the DFB has now asked for a detailed explanation from Ancelotti on the sequence of events.
Bayern released a statement on Monday, which read: "The supervisory committee of the DFB has on Monday called upon Carlo Ancelotti to submit a statement on the events that transpired after Bayern's match at Hertha Berlin on Saturday.
"The Bayern head coach will of course comply with this request."
A fiery game ended in a 1-1 draw, with Robert Lewandowski scoring a controversial stoppage-time equaliser after the initially allocated five minutes of added time had been played.