Faupala, who has featured for France at Under-18 level, joins City on a free transfer after his contract with Lens expired earlier this summer.
The striker did not make a first-team appearance for Lens and is expected to link up with City’s academy side.
Faupala had been targeted by Watford in January last year but Lens had prevented him from leaving.
"When I wanted to leave the Lens at the end of last season, the club prevented me and showed that it will not rely on me in the future," he said in December.
"I will therefore leave Lens for free at the end of season and unfortunately it will be without regret."