Here's an english translation of paper "Multitouch & Natural User Interface: Opportunities for a Bottom-Up Approach" presented at Forum sur l’Interaction Tactile et Gestuelle (June 10-12, 2010 – Euratechnologies – Lille). And here are the slides of this session.
If this subject interests you, take the time to learn about works realized since 1997 by Michel Beaudouin-Lafon at LRI-CNRS on "Instrumental Interaction".This is a great source of inspiration for all NUI enthusiasts.
Thanks a thousand to Hugo Dahl (Dallas, Texas) for his great work on the translation of this paper.