Barcelona buy defender Mathieu for €20 million
Valencia's French defender Jeremy Mathieu celebrates after scoring during the UEFA Europa League semi-final second leg against Sevilla at the Mestalla stadium in Valencia on May 1, 2014 - by Jaime Reina
Barcelona have been seeking to bolster their defence since Carlos Puyol ended his career.
Though he is not an established French international, Mathieu is recognised as a powerful operator at left back and in central defence. Barcelona called him a "physically imposing defender".
The Catalan club had made several offers to Valencia for Mathieu who last week issued a public letter calling on the side to negotiate his release.
"I have a chance to play for the world's biggest club and that's all I want right now," he said.
Barcelona said in a statement it had reached agreement on a transfer and Mathieu would sign a four season contract.
"The cost of the transfer is €20 million and the buyout clause will be €50 million," it said.
Mathieu played at Sochaux and Toulouse in the French first division until he joined Valencia in 2009.