"It is with pride that I announce my decision to join the Algerian national team," Guerri, 23, who defends the colours of Rennes, wrote on his Instagram account, adding: "I will give my body and soul for the Desert Foxes shirt, raise the country's flag and contribute to writing the next pages of its rich history."
Guerre, who has played for France in all age groups from under 16, said he was grateful for the memories of playing for the country where he was born, before adding: "It's time to start a new chapter."
The decision puts an end to months of anticipation after the Algerian Football Federation announced in January that Gueriri was moving to change his international loyalty.
The former Lyon and Nice striker scored 15 goals in 33 appearances in the French league last season after joining Rennes.
Algeria won the 2019 Africa Cup of Nations for the second time in its history, but was knocked out of the group stage in last year's postponed 2021 edition due to the COVID-19 pandemic.