The 22-year-old was one of the stars of France's 2010 RBS Six Nations Grand Slam success, but he has subsequently fallen down the pecking order and has been omitted from Marc Lievremont's preliminary World Cup squad.
Bastareaud had spent his entire career with Stade Francais but the club's financial problems allowed him to secure the move which he believes can resurrect his career.
"I'm super excited," said Bastareaud, who was infamously sent home from a tour of New Zealand in 2009 after falsely alleging he had been assaulted.
"It is a legendary club. Great players have come here and I want to put my name in the history of this club.
"I know most of the players here, which will make things easier.
"I made mistakes but the past is the past, I have left my little cocoon to finally become a man."
Fellow new signings Willie Mason and Mafileo Kefu were also greeted by a 4,000-strong crowd at the club's training ground.
Gilbert has released a new line of rugby cleats. The Gilbert Virtuo 8S is part of the exciting new product. Check it out.
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