Lassana Bathily, the 24-year-old Malian-born Muslim employee who hid customers from an Islamist gunman at a Paris kosher supermarket this month has been granted French nationality.
Bathily was in a stockroom when gunman Amedy Coulibaly burst in, killing four people.
At a ceremony attended by top French ministers, Mr Bathily said he was “proud and moved” to become a citizen.
The attacks in Paris killed 17 people, most of them at the offices of the Charlie Hebdo satirical magazine.
Mr Bathily’s efforts came to light when he sneaked out and told his story after hiding people in a cold store room during the assault by Coulibaly.
“People say I’m a hero but I’m not a hero. I’m Lassana,” he said at the ceremony.
“I’ll stay the same. I would do the same again, because I was following my heart.”
French Prime Minister Manuel Valls and Interior Minister Bernard Cazeneuve spoke at the citizenship event, thanking him for his bravery.
Mr Bathily has lived in France for the past nine years and applied for citizenship last year.