This study used an ethological approach to explore the behavioural adaptation of nineteen infants during their first six weeks in Residential Care (RC), or a Foster Family (FF) or an Infant-Mother Centre (IMC). Direct observations were conducted once a week at bath time. Observed behaviours were: sleep-wake states, visual exploration, motor activity, facial and vocal expressions. Non-parametric analyses showed that, in RC, the duration of bathing was the shortest and babies expressed more crying and withdrawal and less locomotor abilities and vocalizations. By contrast, in IMC, the bathing time was the longest and babies spent the least time in crying and showed the most locomotor abilities and vocalizations. The placement in FF showed intermediate results. This study showed sleep-wake states and behaviours that found variable expression depending on the placement environment and therefore could be considered as markers of the baby's adaptation to his placement milieu in follow-up quantitative studies.