Debuchy, 28, is Arsene Wenger’s second signing of the summer and a direct replacement for Bacary Sagna, who has joined Manchester City.
“I’m very proud to be joining a great club like Arsenal,” he said. “Playing again in the Champions League is a big excitement for me and I will do my best to help Arsenal compete for trophies.”
Wenger believes he is a perfect fit for his side. He said: “He has shown he can perform at the highest level. He is a quality defender who has good Premier League experience and I’m confident he’ll fit in very well.”