Kourtney Kardashian -- She's the New Menace in Justin Bieber's Old 'Hood

Justin Bieber's gone, but residents of his old Calabasas gated community think they have a new demon neighbor ... Kourtney Kardashian.

Neighborhood sources in The Oaks tell TMZ ... residents complained to the homeowners association after TV crews set up a "movie type production" outside the mansion Kourtney recently bought from Keyshawn Johnson.

Our sources say neighbors were pissed because filming is not permitted inside the gated community ... and because the crew was there well into the night -- when contractors, gardeners and other workers are not allowed.

Sources close to the Kardashians tell us the cameras were there for one day of exterior shots for "Keeping Up with the Kardashians" ... and won't be back.