Sene has spent the past two-and-a-half years playing with Bayern's reserve team, where he tallied 19 goals in 55 appearances, including 11 goals during the 2009-10 campaign.
"We had the chance to have Saer in camp with us in Arizona and see him interact with our players both on and off the field," Revs general manager Michael Burns said. "We believe he'll play a valuable role for us this season. He's scored goals consistently with each of his previous clubs, and we believe he has the ability to continue to do so in MLS."
The 25-year-old missed most of the 2010-11 season because of injury, but has bounced back to score eight times in 16 games in the first half of the current campaign.