Makoun came to prominence at Lille, where he made nearly 200 appearances over six seasons, attracting interest from several sides across Europe, including Juventus and Arsenal.
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He ultimately moved to Lyon in 2008, where he has continued to impress both domestically and in Europe - scoring the Ligue 1 side's winning goal in the home leg of last season's Champions League Last 16 victory over Real Madrid.
"Villa have been after me for quite a while, so I am delighted it's finally happened. I can't wait to get started now", the 27-year-old midfielder said on the club's offical website.
"I've left a very good club in Lyon, a side which has played Champions League football, but I am very excited by this new challenge at Aston Villa. Villa really want to do well and really want to achieve something, so I am really excited to be joining."
Speaking of his first acquisition as Aston Villa manager, Gerard Houllier said; "Jean is a player who can play in front of the defence as a sitter and defensive midfielder or as a box-to-box midfielder. He has several assets about his game. He is also a very experienced player because he played Champions League football with Lille and Lyon."
Makoun will be eligible to play once he has received a work permit, a process that could take up to two weeks, according to his new club.
