In the last few decade, in the field of child welfare, the debate on assessment to determine both needs and aims of a social intervention has been developing. This research focuses on a mental health care intervention designed for children with behavioral disorders. The children come to the intervention site once school is finished. The intervention team offers care services, but in some situations the question of a possible intervention of child protection services may emerge. The team of mental health clinicians becomes then actor of the assessment process. A comprehensive methodology based on a participant observation enables us to get a better understanding of the clinicians’ practice and address the question of their relationship with child protection services. To underline the different factors which interact with the decision process of the clinicians we use the decision making ecology. We first define theoretical frameworks which structure the team practice. Then we identify constraints such as the French rules of child protection services and strategies used by clinicians such as their expertise position and by child protection workers such as their intermediate position to understand how their relationship is built. We also highlight that the clinician team rather than stressing out the risk of danger for the child may decide to contact child protection services when parents are not able to elaborate on their difficulties. These results lead to a new understanding of social workers’ intervention. Aims are not anymore to conform individuals to the social rules but to help them to elaborate on their difficulties to anticipate and deal with them with a demand of self-realization in mind.