The death of the 33-year-old Frenchman, killed during a raid by anti-terror police, has reignited terrorism fears in the country, France24 reported Wednesday.
Prosecutor Francois Molins said Louis-Sidney was a recent convert to Islam but little is know about him.
He appears to have been a home-grown militant, radicalized on French soil.
French police identified him as a suspect in the Sept. 19 bombing of a kosher grocery store in the northern Parisian suburb of Sarcelles.
A Salafist network is believed to be behind the incident.
Police sources told France24 DNA identified on the grenade used in the blast was traced to Louis-Sidney.
When police went to his apartment to arrest him, Louis-Sidney fired at officers, injuring three of them before he was fatally shot.