Franco Sebastian Sosa is a professional footballer from Argentina who plays as a defender. He began his professional career in 2001 with Gimnasia de Jujuy where he stayed for 7 seasons. As part of the Primera B Nacional division in Argentina, he was influential in Gimnasia winning the 2005 Clausura title and gaining promotion to the Primera Division. He stayed on for one more season and made more than 120 appearances for the club, scoring 7 goals.
In 2007, he shifted to Racing Club where he was a regular in the starting lineup, scoring 6 times in almost 70 games.