Coquelin left the Gunners in January.
“It isn't that easy when you've spent 10 years somewhere, but I needed a new challenge," Coquelin told Clicanoo.
“You tend to get into a comfort zone when you stay several years in the same clubs.
“You try and challenge yourself, but it's a bit harder. Here, I'm starting from scratch. It's a new experience, a new training method, new teammates and a new environment.
“All that means I was thrilled by the project. There are interesting goals to accomplish. I'm focused on that."