According to a statement released by the big-spending Top 14 club, Henson breached the club's disciplinary code.
No further reasons have yet been given why the 2005 Lions tourist was slapped with the suspension which rules him out of this weekend's clash with Perpignan.
The 29-year-old only moved to the south of France in February but has enjoyed a promising start to his revived career.
Henson scored one try and set-up another in the club's victory over Stade Francais two weeks ago and was again in fine form in the win over Toulouse on Saturday.
Toulon are currently one place and one point outside the Top 14 play-off positions but if they fail to qualify Henson would have just one game left to play.
While Henson is aiming to play his way into Warren Gatland's World Cup plans he is also playing for a contract at Toulon having only signed a short-term contract.
Wales backs coach and former Lion Rob Howley recently revealed Henson could make his international return in this summer's pre-World Cup internationals.
"We're watching Gavin very closely and he'll certainly come into the mix in our Rugby World Cup preparation," said Howley.
"We want to give him an opportunity because he's spent a long time out.
"He looks very fit. We all know Gavin's strengths, he's a very accomplished player, very skilful and he's very confident in his own rugby ability.
"His ability to play 12 or 13, with a kick, run, pass option, he is a very confident rugby player. I think that his game-time is going to be monitored between now and the end of the season."