"The child and the city or the child within the city constitutes initially, for one is interested in the development of the former, a paradoxical relationship. Indeed, the child faces varied intensive stimulations and complex and rich informations. He is taken, despite him, in a contradictory report: the city is a social and spacial experience place and at the same time a place safeless, sometimes threatening, from where lie is held off and from where his security may sometimes be built excessively by adults. Consequently, we propose to show how the child's environmental autonomy varies according to the urban environment type, more specifically according to physical and social qualities, as well as to the nature of dangers to which the child can be confronted. Purposely, this study consists of articulate interrelations among child's mobility-behaviors (range of environmental experience and journey homeschool) and child's and adult's representation of danger. A sample of 10-13 year old children was interviewed at school individually. They come from different neighborhoods which differ in their urban structure (traditional neighborhood with road danger presence, and a "new town" neighborhood with adjustment of pedestrian systems distanced of all road dangers). We have proceeded as following: (1) cognitive map of the journey home-school (to allow, on the one hand, to evaluate objectively the type of dangers to which the child is confronted and on the other hand to observe the representation of the danger); (2) cognitive map of the territorial home-range and range of experience around the home (to measure the degree of the child's mobility as well as his environmental barriers); (3) open-ended questions beside children and parents. What imports us in this preliminary work, is not to show it may exist dangers in the urban environment, but rather to understand how this reality is perceived. We will pose the system of representations through which the environment and its dangers are appraised by parents and their child. At first, we will show that modes of appropriation of a situation by parents then by the child (attributed meaning and its system of representation) lead the child and especially parents to accept or not disadvantages of the urban environment as well as they lead to place in terms of practices in a report of confrontation or avoidance. Finally, experience range and therefore child's environmental autonomy differ according to urban structure environment."