The Uruguayan was keen to leave Parc des Princes in search of regular playing time and he has accepted an offer from the La Liga side.
AS understands that the deal does not include an option to purchase the player’s contract at the end of the season.
Lugano arrives at La Rosaleda to provide competition for starting centre-back pairing of Martin Demichelis and Weligton.
The 32-year-old will attempt to get his career back on track after what was a very disappointing spell at Parc des Princes.
Lugano joined the club from Fenerbahce in the summer of 2011, but has since made just 12 Ligue 1 appearances for the Saints.
He has been completely frozen out of the squad this term and failed to feature in a single competitive match.