This paper presents a new application that aims at improving communication and interactions between digital media and customers at a point of sale. Our system analyzes in real-time human behaviour while shopping. In particular, the system detects customer's interest in products and interaction such as people grabbing products. This system is based on a behaviour model. A video analysis module detects motion, tracks moving object, and describes local motion. Then specific behaviours are recognized and sentences are generated. Finally, our approach is tested on real video sequences.