Emery brought through the 18 year-old forward while in charge of PSG last season.
Weah, the son of George Weah, told L'Equipe: "I'm happy, I played a few games, in the national team I scored my first goal, I can create something from this end of the season.
"I took my chance, I want to thank the coach Emery and his staff, they could take any player, they took me, he gave me confidence. I am very happy, I was really surprised.
"It is a sick level, I have progressed a lot. At each training, I progress. I will develop my game with PSG."