The former Manchester United star chose the day of his 35th birthday to transmit the news via his Twitter account.
Saha began his career at Metz in 1997 before moving on loan to Newcastle United in the second half of the 1998-99 season.
He came back to England in 2000 when he joined Fulham and his form there saw him catch the eye of Alex Ferguson, with a move to United ensuing in January 2004.
He won the UEFA Champions League in 2008 and two Premier League titles during his four-and-a-half year spell at Old Trafford, before moving on to Everton.
Further spells at Tottenham Hotspur, Sunderland and Lazio came as his career wound down.
He also played 20 times for France, scoring four goals and taking part at EURO 2004 and the 2006 FIFA World Cup, where he helped France reach the final, for which he was suspended.