She said that the gunman - since identified as Said Kouachi, the older of the two brothers - said that he was "sparing her ... and because I am sparing you, you must read the Koran".
Ms Vinson is a former actress and lawyer, now a novelist and commentator on legal affairs for Charlie Hebdo.
Her long account in Le Monde is the most detailed yet published of the massacre at the satirical magazine a week ago in which 12 people died, including two police officers and a visitor.
She recalled the mood of the magazine's weekly editorial meeting just before the gunmen burst in - full of New Year's greetings, cake-eating and doubtful jokes about oral sex.
Watch:
New footage of Paris attack
The magazine's red cocker spaniel, Lila, went from person to person, seeking titbits.
After the gunmen attacked, Ms Vinson said, as she lay terrified on the floor, she could hear the "pitter-patter" of the dog's feet going from body to body.
Lila was not injured in the attack.
"They are all dead"
The first that the meeting knew of the assault was the "pop pop" of two shots fired in the outer office.
A police protection officer, Franck Brinsolaro, jumped to his feet and fumbled for his gun. He was killed a few seconds later.
The door of the conference room burst open and a man shouted "Allahu Akbar" (God is the greatest) and then "Where is Charb?" (Stéphane Charbonnier, known as Charb, the editor and chief cartoonist of Charlie Hebdo, who was also killed).
Ms Vinson threw herself on to the floor and crawled to a neighbouring office space, shielded by a partition. She heard the gunmen firing calmly and steadily.
"It wasn't a burst of gunfire. It was shot after shot after shot," she said. "No one cried out. Everyone was dumbfounded."
She heard the footsteps of one of the gunmen coming into the room where she was hiding. It was then that she looked up and saw the killer's eyes.
"As he was talking, I kept nodding," she said. "To keep a link with him, a contact. Perhaps, without knowing it, I was trying to soften him.
"I didn't want his eyes to leave me because Jean-Luc [a layout artist, who also survived the attack] was lying under the table beside me. [The killer] hadn't seen him.
"I understood well enough that, if he wasn't prepared to kill women, he was happy to kill men."
When Ms Vinson returned to the conference room, it was a "vision of horror", she said.
Bodies lay everywhere. One colleague who survived had his cheek ripped open by a bullet; another, shot in the legs and stomach, was dying.
She called the emergency services. In her shocked state she could not remember the address of her own office.
She screamed over and over: "They are all dead."
- Independent
