The Frenchman had a miserable time at the North London with regards to matters on the pitch as he only featured in 13 Premier League games across four-and-a-half years.
During that time the right-back had injury problems, mainly with his heel and shoulder, which needed operating on, and he had a loan spell at Bordeaux in 2016.
On transfer deadline day, Debuchy was released from his Arsenal contract and signed for Saint-Etienne for the rest of the season.
"It is a relief," the Frenchman told L'Equipe. "Even if Saint-Etienne are going through a delicate period, it is still a mythical club. To play in such a stadium, with the fans always behind the team, is great.
"My priority is to get a run of matches and rediscover the rhythm and pleasure of playing and above all help the club. Of course, in the back of my head, I still have the challenge of getting back in the France team, but I have to do things in order and first I have to help Les Verts."
Debuchy made seven appearances for Arsenal this season, all of which were in cup games.