The attack left her with a moderate-sized bite wound on her leg and lacerations to other parts of her body.
She was then dragged out of the water by her friends.
She remained calm after the attack and "handled it very well".
"She was conscious the whole time, but had a pretty good gash on her leg.
"There wasn't a ton of blood. Obviously, it wasn't an arterial bleed," Smart said.
It would need a lot of stitches.
Smart had just finished a surf lesson and was back at his office when the attack happened.
"I looked down the beach and I saw someone running and I just thought something wasn't right."
He quickly drove down to the beach and, after learning it was a shark attack, called 111.
He got his stretcher and took the woman to a friend's house near the beach, where they put pressure on the wound and kept her warm by placing her next to a fire.
"Emergency services cut her wetsuit off and applied a lot of pressure."
Although the injury was serious, he believed she would fully recover from the attack.
"She's not losing her leg or anything like that, but she has got some pretty good wounds.
"It will definitely take a while to heal up those wounds."
He was full of praise for the response from emergency services, which he called "textbook".
He was unsure what type of shark it was and did not want to speculate, but believed it was a shark rather than a sea lion.
It was not common to see sharks in the area.
He had only seen small and "very docile" sharks in the past.
The last shark attack at the beach was three years ago.
"The two shark attacks we have had at this beach, to me, that's the worst of attacks ever ... in the history of surfing in New Zealand. It's just unfortunate both times happened to be at Curio Bay."
Department of Conservation marine scientist Clinton Duffy said a range of shark species could be found in the area, including great whites, mako, blue sharks and broadnosed seven-gill sharks.
"And the species most likely to be involved in an attack is either going to be a seven-gill or a great white shark."
It remained extremely rare for swimmers and surfers to encounter sharks in the wild, let alone be attacked by them.
A St John spokesman said the woman was taken to Dunedin Hospital's emergency department with moderate injuries.
A spokeswoman for the Southern DHB this morning reported the woman was in a stable condition.
The French Embassy has been contacted for comment.
- Otago Daily Times, with additional reporting by New Zealand Herald