The 31-year-old joined Rennes on loan in January having made just two league appearances this season, and has hit out at the "well known" agent behind his move to Upton Park
The 31-year-old had signed a three-year deal with the Hammers over the summer, but secured a loan move back to his homeland having made just two Premier League appearances prior to the transfer window opening.
And Diarra has now blamed West Ham and a "well known" agent for making false promises in order to lure him to Upton Park.
"The club has not been honest with me,” Diarra told France Football. “They made me believe I was the priority of the club, but it was not true. Evidence that at my age you can be fooled.
"This is the story of a British agent, well known, that tells anything, that makes you travel by private jet, who also makes you sign a purchase contract. This is convincing. But he did not care for the man, the player."
The Frenchman also expressed dismay at the way he was treated by manager Sam Allardyce during his time in England.
"I thought I had played a good Euro 2012 on a personal level, I played a good game against England," he said.
"I was in the quarterfinals of the Champions League with Marseille. I thought I could help a team that rose from the Championship.
"But I was not given the role I wanted. I was just another player. I worked in the shadows, but this work did not serve. Sam Allardyce was always travelling. I wanted to talk to him. But he prioritised his players, who have been here for several seasons.
"I could not accept this situation and I went see my managers to ask them to leave. They understood me, so I thank them.”