The father of a young child saved from a fourth-floor balcony was out playing Pokemon Go at the time of the dramatic rescue, prosecutors say.
The father of the child was later detained by police for alleged parental neglect and now faces up to two years in prison when he appears in court in September.
The man left his four-year-old alone to go out shopping, before delaying his return to play Pokemon Go on his phone, prosecutor Francois Molins told BFM-TV.
As well as being made a French citizen, Mr Gassama will be offered a place in the fire brigade for his bravery.
After meeting the 22-year-old at the Elysee Palace, French President Emmanuel Macron described the rescue as an “exceptional act”.
He told Mr Gassama: “You saved a child. Without you, no one knows what would have become of him.
“You need courage and the capability to do that.”
Avec M. GASSAMA qui a sauvé samedi la vie d’un enfant en escaladant 4 étages à mains nues. Je lui ai annoncé qu’en reconnaissance de cet acte héroïque il allait être régularisé dans les plus brefs délais, et que la brigade des sapeurs-pompiers de Paris était prête à l’accueillir. pic.twitter.com/xMpFlP1UFe
— Emmanuel Macron (@EmmanuelMacron) May 28, 2018
He added Mr Gassama had become an “example” because millions had viewed the astonishing act after footage was uploaded to Facebook.
The migrant admitted he was “trembling” after the rescue, but told the French president: “When I started to climb, it gave me courage to keep climbing.”
Mr Gassama also received a medal and certificate for bravery on his visit to the presidential residence.
Footage showed Mr Gassama pulling himself up from balcony to balcony in a matter of seconds, while a man on the fourth floor tried to hold on to the child by leaning across from a neighbouring balcony.
On reaching the fourth floor, Mr Gassama put one leg over the balcony before reaching out with his right arm and grabbing the child.
Firefighters arrived at the scene to find the child had already been rescued. A spokesman said: “Luckily, there was someone who was physically fit and who had the courage to go and get the child.”
Mr Gassama has been living illegally in France and working in construction since September last year after making a perilous journey from his homeland via Libya and Italy.
He previously told reporters he acted without thinking.
“I saw all these people shouting, and cars sounding their horns. I climbed up like that and, thank God, I saved the child,” he said.
“I felt afraid when I saved the child… [when] we went into the living room, I started to shake, I could hardly stand up, I had to sit down.”
Prior to his visit to the Elysee Palace, Mr Gassama had already been thanked by Paris mayor Anne Hidalgo in a telephone call.
“He explained to me that he had arrived from Mali a few months ago dreaming of building his life here,” she said.
“I told him that his heroic act is an example to all citizens and that the city of Paris will obviously be very keen to support him in his efforts to settle in France.”