Sunawin Andrews filed a request for the ban in Los Angeles County Superior Court earlier this month (Mar10), stating they fell out in July (09) after the Irish actor returned home from a film festival drunk.
According to the legal papers, Fassbender, who won critical acclaim for his role as Irish hunger strike leader Bobby Sands in 2008's Hunger, reportedly woke up in his own urine and started becoming violent towards Andrews, before he "threw (her) over a chair and broke (her) nose".
But that wasn't the only violent episode he displayed, according to his ex.
She also claims Fassbender dragged her alongside their car on another night after an argument about one of her ex-boyfriends. On that occasion, Andrews alleges she was left with a twisted left ankle, a blown knee cap and a burst ovarian cyst.
Andrews is seeking the court approval of the restraining order request to keep Fassbender at least 100 yards away from her and her two kids at all times. She is also requesting $20,000 (£12,500) in compensation to cover her medical bills, reports TMZ.com.
The actor, 32, has yet to respond to the allegations.