@pbrad: yep, you're right, I used a physically correct render :) My setup is similar to what you can found in the file "Studio render of Nissan Pathfinder", here:
So thanks to the Emirage for the fantastic set-up.
The environment is finished, here's a clay render:
I took inspiration from one of the last tutorial of Andrew Price (here http://www.blenderguru.com/how-to-create-realistic-outdoor-lighting/) adding a bit of details, and a hdri to to improve the reflections.
It seems over exposed, but adding the texture should fix it.
And here the wireframe as promised:
The barrels and the shutters were first modeled perfectly straight, and then twisted and ruined using lactice.
I also uv-unwrap all the models that I need:
The next step is the material/texture!