Ergonomic interventions in support of architectural projects involve helping to define the working environment by placing work activity at the heart of the reflection on the future. The request for our intervention came from the staff of a multidisciplinary primary health care facility. The objectives of our intervention were to optimize space to improve care provision and meet the pressing demands of patients. This was a two-steps intervention. The first phase was an open observation of work activity, supplemented by a second phase of individual semi-directive interviews. Based on the results of the activity analysis, architectural adjustments were proposed. Our study revealed unequal and inadequate exploitation of spaces, resulting in a disorganized patient and healthcare staff flows. In addition, due to patients overcrowding noise levels were becoming disabling, both for patient examination and for staff comfort. Recommendations and conclusion: A new architectural plan was proposed and adopted by the ministry of health. This plan aimed to separate patient’s flows by dividing the large waiting hall into two sub-areas and using the two existing entrances. This allowed us to separate pediatric consultation from adult consultation. Our recommendations included a forward-looking approach to anticipate future developments. A periodic evaluation of the job satisfaction of staff and that of users in the new care system to define the success or otherwise of the approach is crucial.