exclusive
Doug Reinhardt -- former Paris Hilton BF who appeared on "The Hills" -- has been hit with a temporary restraining order after allegedly threatening to "beat the f**k" out of his neighbor, TMZ has learned.
The 29-year-old -- who's also the heir to a frozen burrito fortune -- has been living in a $15k-per-month home above the Sunset Strip, according to legal docs ... and his next-door neighbor says he's been a total nightmare.
The main issue ... the neighbor, a bigtime real estate agent, claims Doug's been throwing crazy parties that don't START until 2:30 AM.
And when the neighbor complained, he says Doug called him a "pain in the butt" and said, "I'm going to beat the f**k out of you."
The neighbor says he fears for his life ... and begged the courts for protection.
We've learned ... the judge issued a temporary restraining order against Doug, requiring him to keep his distance from the guy -- a whole 5 yards (since they're neighbors, any other distance would essentially require one of the parties to move).
We tried reaching out to Doug for comment -- so far, no word back.
