Universal Music Sued For Unauthorized Sample in Mary J. Blige's 'Real Love'

Universal Music Group is facing a new lawsuit ... and it all has to do with Mary J. Blige's most famous song -- which someone is now claiming illegally sampled an old jam.

According to new legal docs, obtained by TMZ, a company called TufAmerica, Inc. -- which owns Tuff City Records -- is suing the music publishing giant, claiming it sampled their song "Impeach the President" in MJB's "Real Love" without getting permission.

"Real Love" allegedly uses an uncleared sample from "Impeach the President" in both a sound recording and the musical composition. Tuff City claims they've reached out to UMG over the issue, but Universal hasn't addressed their concerns ... so, now they're suing.

What's interesting is that if you look into what song is actually credited as the sample for "Real Love" -- it's actually another hip hop song that came out in the '80s called "Top Billin'" by Audio Two ... and if you look at that song and what they sampled, 'ITP' is in fact listed.

Tuff's suing for damages and wants to stop Universal from continuing to profit off its sample in "Real Love" until the matter's resolved. BTW ... Mary is not a defendant in this.