Diarra has been without a club since leaving West Ham United last July and the former Liverpool and Bayern Munich midfielder will hope to impress coach Frank Yallop enough to earn a long-term deal with the Fire.
The 33-year-old Frenchman has made 44 appearances for his country and was a part of the French squad at the World Cup in 2006 and 2010.
He has spent most of his career in France but the chance to play football again with the Chicago Fire will be a challenge Diarra will hope becomes a reality.
The experiences midfield enforcer is a natural leader and his combatative style of play has seen him compared to Michael Essien and Patrick Vieira throughout his career.
The Fire squad drew 0-0 with Norwich City on Thursday and they are now in London training with Queens Park Rangers ahead of a friendly with the Premier League side this Thursday.
Diarra will hope to impress in that game and he could be the latest addition to a Chicago squad that has seen 13 players brought in this offseason.
Would Alou Diarra be a good signing for the Chicago Fire?