In social mammals, conflicts are stressful events for the individuals involved. In the post-conflict context, it is possible to detect the emotional state of the former opponents through the expression of displacement activities and aggressive behaviours, which indicate an increase of social tension. In humans, stressful events also induce a physiological response which leads to increased social tension behaviours. However, the variation of such behaviours in the post-conflict conflict, has never been investigated. By conducting a video analysis of street fights recorded by Close Circuit Television cameras, we assessed the variation of behaviours associated with anxiety, aggression related anger and other behaviours possibly related to both anxiety and anger (body postures and talking with gestures) in human opponents. We compared the expression of social tension behaviours before and after the eruption of the conflict and found that displacement activities (related to anxiety), aggressive behaviours (related to anger) and talking with gestures (possibly related to anxiety/anger), but not body postures, increased in post-conflict context. Moreover, displacement activities and aggressive patterns showed a temporal variation, decreasing in the 10 minutes following the conflict. Finally, different from anger-related behaviours, the level of anxiety-related behaviours was more sensitive to aggression intensity, indicating that different social tension behaviours rely on different responses that might be separated. With our study we were able to highlight the importance of the ethological approach for the study of post-conflict social tension in humans, which show a variation in its expression as observed in nonhuman primates. Following a similar comparative approach, we encourage further studies to explore the role of social tension in affecting post-conflict social dynamics.