How can I get a look like these photos? Thank you http://de.volkswagen.com/de/models/polo/galerie.html
This is not as simple as an "effect."
Something like this absolutely is possible, but it takes a lot of work before and after pressing the shutter.
Taking the picture:
The key part of the look, from a technical perspective, is the light. In 3D renderings, light can come from anywhere, from a source any size, and in any color, so renderings like these have near-perfect lighting and have very regular reflections. This could be replicated by shooting at midday (note the location of the "sun" based on the reflection and shadow) and then using large soft boxes with flashes to draw extra highlights on the metal (that's what gives it the super-shiny look)
Shoot at very low ISO, very high speed, and optimal aperture (f/5.6 to f/8, roughly). In this case, a lot of the styling is going to happen in postproduction, so making a highly accurate recording of everything in the image is the best idea; decisions like focus and sharpness can be made later in photoshop.
An image like this is as much illustration as photo, artistic vision matters and there are no such things as "magic sliders."
Clean everything: remove all the dust, pavement cracks, wall stains, stray dirt, everything that you wouldn't include if you were drawing the image of the car by hand.
Layers, foreground and background at a minimum
Paint colors and contrast on the background: most of these images have a subtle teal to orange gradient across the background, this could be recreated on a real photo using gradients and brushes in photoshop if the composition of the image allows.
Microcontrast: These images have low global contrast, but the micro contrast (such as within the reflections on the sheet metal) is quite high—this is what ezmopho meant by the "clarity slider" which (among other things) is a contrast/microcontrast slider.
In short, it's really difficult to produce media of this quality whether or not you use a digital camera or a rendering (much of the post-work, like colors and contrast, would be very similar). Light is first and foremost, as with all photography, and the post-processing shapes the colors and texture of the image to feel like a drawing.
You can get a similar look with Adobe Photoshop Lightroom and the "Clarity" slider. Move it all the way to the left, and it reduces contrast, and just sort of gives it a smooth creamy look.