The 24-year-old has not featured for The Hammers this season and made just eight appearances for the club during his 15 months at the club.
The former Toulouse ace is expected to return to his native France and Hammers boss Glenn Roeder admitted the player had found it difficult to settle at the club.
"Laurent has had his contract cancelled by mutual consent and from immediate effect," said Roeder.
"Laurent couldn't force his way into the team and has found the last six months difficult. He wants to go back to France to play and I wish him well."
Roeder is also hopeful of bringing in a new striker to bolster his firepower before the transfer window closes.
"We have our number one target (Lee Bowyer) and we are still hopeful of signing one more player - a striker - before the window closes," added Roeder.
Roeder has been continually linked with Tottenham's Les Ferdinand who looks set to leave White Hart Lane.
