They report: Benabou claims he worked for Bieber from March 2011 to Oct. 2012 and the popstar berated him and punched him in the chest multiple times during a disagreement about how to handle a member of his entourage.

Benabou is seeking unspecified damages for assault and battery as well as more than $420,000 in unpaid overtime.

But sources in Bieber's camp tell TMZ ... Moshe is nothing more than a "disgruntled employee looking for money." They say the claim that Bieber struck him is "absurd."