The 29-year-old has agreed a two-year deal at The Valley after his contract with Greek side Panetolikos FC expired.
Bikey becomes Charlton's fourth signing of the summer after a successful trial period at the club, including an appearance in Sunday's 0-0 friendly draw with Sint-Truiden in Belgium.
"He made a very good impression with us in Belgium," Valley boss Bob Peeters told the club's official website.
"He's got experience of this league and we're very happy to sign him. His knowledge of the Championship will be very important."