Tanya St-Arnauld (QMI photo)

A woman who was disfigured in an acid attack last summer testified Monday at her ex-boyfriend's preliminary hearing.

Tanya St-Arnauld bore burn marks across her upper body as she took the stand in the suburban Montreal courthouse.

Her testimony at the hearing for Nikolas Stefanatos can't be reported because of a publication ban.

Stefanatos, 27, is charged with assault in the attack just outside Montreal in August.

A boiler that stored acidic concrete cleaner was poured on top of St-Arnauld on the top steps of her apartment.

She suffered burns over 20% of her body.

St-Arnauld was in a coma and has since undergone several excruciating skin grafts, including on her scalp.

Stefanatos has been held behind bars since the attack.

A judge denied him bail last fall, calling the attack "a very serious crime, which demonstrates gross carelessness towards physical integrity and towards women."

The defence contends that the defendant has a drug problem and needs treatment in the community.