Schweinsteiger scored Bayern's equalizer in Tuesday's 1-1 first-leg draw in Manchester but was later sent off after picking up a second yellow card for a foul on Wayne Rooney.
Bayern complained in an emailed statement Thursday that the Daily Mirror and The Sun "'reported' in disrespectful, discriminatory and personally abusive manner" on Schweinsteiger. It attached pictures of a Sun story headlined "You Schwein!" and a Mirror story headlined "You Dirty Schwein."
Defending champion Bayern's second-leg match against United will be played at the Allianz Arena next Wednesday.