A very interesting insight into the '4 minutes' video special effects is available on French site 3DVF.com.
They interviewed Julien Meesters, Benoit Holl and Fabrice Macagno from Mikros Image, the post-production company which was in charge of the special effects.

You can download a one-minute-long making-of as well by clicking here.

Click here to find out more about this great insight (article is in French).

Source: 3dff.com, Madonna Tribe