Most of the members of the cast are friends into real life, knowing each other from fifteen years and more (and sometimes the name of the actors and those of characters are the same). They went into a two months and a half acting workshop with the two directors, and improvised a lot of situations on the basis of a script full of very well defined dialogues.
The workshop lasted two-and-a-half months, the shoot lasted only five weeks.
The movie was shot with three cameras always shooting on set, so that actors had to perform all the time, regardless to any idea of "plan": as a matter of fact, they acted knowing not if they were shot in a close-up, a long shot or they were not in any plan at all.