According to egmCarTech, it is the 2012 3 Series Prototype.
"The car you see in the video is a camouflaged 2012 BMW 3-Series, which will be unveiled to the public later this year (most likely at the 2011 Frankfurt Motor Show).
Don’t get to excited because you really can’t see much of the car’s exterior or interior..."
http://goo.gl/yrF3m