Coworking spaces are places for social interaction, encouraged by the co-presence of workers in an open space (Weijs-Perrée et al., 2018). Nevertheless, the uncontrollable and discontinuous noise of telephone or face-to-face conversations can reduce concentration (Pierrette et al., 2014). Faced with the different layouts of coworking spaces, workers develop specific practices (Bouncken and Reuschl, 2016). Certain parameters of the open space (occupancy density, sound environment, etc.) could have an effect on interactions and concentration. This effect would be moderated by the activity of the workers. A study is underway in four coworking spaces. One to four volunteer workers are observed for two hours in an open space using a grid. Each observation data point is summarised on a Powerpoint®-type medium. The workers then completed a questionnaire to assess their concentration. In a self-confrontation interview, they were asked about their profile, their practices, their answers to the questionnaire and the observation data. The initial results relate to 52 workers and 23 days. Of the 74 interactions recorded, 65% concerned workers working on the same block; 20% involved the interlocutor moving to the worker under observation. These interactions lasted 3 minutes on average, with half lasting less than a minute. Over 90% of the workers gave a positive assessment of their concentration. Of these, 42% explained this by the fact that there were few people or noisy conversations in the open space, and 15% by the fact that they were wearing headphones or earphones. In fact, the spaces observed were never occupied to more than half their capacity, and 42% of the workers explained that they wore headphones or earphones to isolate themselves from the surrounding noise. These initial results confirm the effect of conversational noise on concentration in open-plan workspaces, and the importance of the activity deployed by workers to moderate it.