Schalke have added to their defensive options by bringing in Nicolas Plestan from Lille.
The 29-year-old spent seven years at the French club, featuring in 109 games, but struggled to earn a starting spot last season.
He made just five appearances after an injury-affected campaign and moves to Germany after agreeing a three-year deal.
Schalke boss Felix Magath has played down fears over the Frenchman's fitness, insisting he was not worried by his recruit's well-being.
Plestan becomes the first French player to join the club, who have also recruited Dutch striker Klaas-Jan Huntelaar and Spaniard Jose Manuel Jurado to boost their ranks.
The former AS Monaco youngster will compete with Christoph Metzelder for a place in Magath's side.
Metzelder was signed in the close season from Real Madrid but has failed to convince during the opening two games of the Bundesliga season, which have seen Schalke lose twice.
Plestan had formerly courted the interest of Premier League side Everton, although no move materialised.