The knowledge about the intervention in the field of occupational mental health has improved considerably, particularly from the point of view of intervention models. However, we know very little about the logic behind the intervention practices. For example, while it is recognized that primary interventions are more effective, these interventions are less prevalent than individual interventions. In addition, knowledge about the effects of interventions is still to be stabilized. Moreover, there is a lack of analysis of the implementation of the intervention based on qualitative methods and a need to focus more on the role played by the processes and contextual variables that influence the intervention. This article proposes to feed the knowledge on the intervention from a qualitative approach and centered on the intervention process. We conducted an empirical research and we considered real intervention. Using the case study, the article shows the real of the intervention, its obstacles and the adjustments it imposes. The model is also inspired by the intervention scheme proposed by the ergonomics which constitute a grid of analysis of the interventions. Eight steps are proposed to intervene by favoring a change in the organization, from the expression of the problem to the institutional decision to direct specific actions. These eight steps are grouped into four maturation periods that are: (1) the definition of the intervention, (2) evaluation, (3) the definition of recommendations, and (4) the decision on the change. The case studied is in a semi-public cultural institution with count 950 employees. The choice of the qualitative method is relevant to capture the real of the intervention and to propose thinking on what participates in the quality of an intervention. This intervention process shows the effects of variation caused by lack of accession and support from management and the trade unions, the difficulty of passing from knowledge to action, and the difficult balance between expertise of consultant and expertise of stakeholders. So, the analysis of the dynamics of intervention helps to understand how positions an organization on this question and opens towards new runways to strengthen the quality of action in occupational health. Finally, the results support us in the desire to work more at an intervention clinic.