The Charlie Hebdo caricaturist who was forced at gunpoint to open the satirical newspaper’s door to two al Qaida extremists has described the moments of sheer terror during the 2015 attack in France.

Corinne Rey had tears in her eyes but her voice was clear as she gave evidence at the trial of 13 men and one woman accused of helping three men plot the attacks on January 7-9 2015 in Paris.

Seventeen people, including 12 in and around Charlie Hebdo’s offices, four at a kosher supermarket and a policewoman, were killed.

All three attackers were killed in subsequent police raids.

Ms Rey had left the weekly editorial meeting a little early to go downstairs for a cigarette when the gunmen came in the door, calling her by her pen name Coco, and ordering her to take them to the Charlie Hebdo offices.

She walked upstairs between the two men armed with assault rifles.

Only at the moment when Ms Rey described leading them accidentally to the wrong floor of the building did she falter, crouching down and holding her arms over her head in a replay of her reaction as the gunmen realised her mistake.

Said and Cherif Kouachi targeted Charlie Hebdo because they believed the newspaper blasphemed Islam by publishing caricatures of the Prophet Mohammed.

They opened fire on the group seated around the offices as soon as they entered, but told Ms Rey they were sparing her life as a woman.

“This is something I will live with the rest of my life. I felt so powerless, felt so guilty,” she said.

Now, she said: “I expect justice to be done here. It is the law of men that rules, and not the law of God, as the terrorists would have it.”

On the day the trial opened last week, Charlie Hebdo reprinted the caricatures.

A relative of one of the militants who attacked French satirical magazine Charlie Hebdo in Paris in January 2015 has been put under formal investigation for Islamist ties and remanded in custody, a judicial source said on Saturday.

The source said Mourad Hamyd was suspected of trying to travel to Syria to join Islamic State.

Hamyd, who is French and a brother-in-law of assailant Cherif Kouachi, was detained in Bulgaria last month after a Paris court issued a European arrest warrant against him.

Hamyd was questioned by French police following the Charlie Hebdo attacks in which Cherif Kouachi and his brother Said shot dead 12 people before being killed by police, but was cleared of any involvement.