LOS ANGELES - A Los Angeles man has become the first person to be convicted under California's new "revenge porn" law after he posted topless photos of his ex-girlfriend on her employer's Facebook page.

The court heard that the woman had obtained a restraining order against Noe Iniguez, 36, in November 2011 after they broke up their four-year relationship and he began sending her harassing text messages, reported the LA Times.

Then in December 2013, under a fake name, Iniguez posted derogatory remarks about the victim on her workplace's Facebook page.

His torment intensified this year when he put up nude photos of her on the same page, calling her a "drunk" and "slut" and encouraging the company to fire her.

Iniguez was sentenced to a year in jail on Monday. He was also ordered to serve 36 months' probation, attend domestic violence counseling, and stay away from the victim.

Enacted in October 2013, the law against "revenge porn", also known as "involuntary porn", forbids people from posting intimate recordings, such as photos and videos, online with the intent to cause another person emotional harm. Once convicted, perpetrators can be thrown six months behind bars and receive a US$1,000 (S$1,250) fine, accordng to the Ars Technica tech news website.

The law, however, does not apply when the recording was made by the victim, according to a Forbes report. Punishment will also be meted out only to the person who makes the recording, not everyone else who distributes the recording.

"This conviction sends a strong message that this type of malicious behaviour will not be tolerated," City Attorney Mike Feuer was quoted as saying by the LA Times.

He added that the new law is a "valuable tool" for prosecutors looking to protect victims "whose lives and reputations have been upended by a person they once trusted".