The French left-back arrives from Valencia.
Rodgers said: "He provides competition for Jose Enrique.
"He's a player that's got experience; only a few years back he went for 15million so he's a player that has got quality. The idea was to build the squad and make it competitive.
"It has allowed the likes of Jack Robinson to go out on loan and get experience.
"At the same time, it was important that we bring in someone that's got that experience, so if anything happens to Jose he can come straight into the team and fight for the position. Hopefully that will get the best out of both of them."
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