Since the population of the elderly grows highly, the improvement of the quality of life of elderly at home is of a great importance. This can beachieved through the development of technologies for monitoring their activities at home. In this context, we propose an activity monitoring system which aims to achieve behavior analysis of elderly people. The proposed system consists of an approach combining heterogeneous sensor data to recognize activities at home. This approach combines data provided by video cameras with data provided by environmental sensors attached to house furnishings. In this paper, we validate the proposed activity monitoring system for the recognition of a set of daily activities (e.g. using kitchen equipment, preparing meal) for 9 real elderly volunteers living in an experimental apartment. We compare the behavioral profile between the 9 elderly volunteers. This study shows that the proposed system is thoroughly accepted by the elderly and it is also well appreciated by the medical staff.