Mr Etier has almost 20 years' experience in the legal field of accidents (road traffic accidents, train accidents, airplane accidents, etc.). He advises and represents claimants and defendants, whether individuals or businesses, in relation to all aspects of civil liability. He conducts his practice by establishing trusting relationships with his clients.

He has lectured on civil liability as part of the Master's degree in civil and criminal law at the University of Geneva for many years. In 2012, he lectured on the Roman foundations of private law at the Universities of Neuchâtel and Geneva.

He also represents private clinics, medical centres, medical groups and doctors in complex areas such as their relationships with health insurers and health authorities, authorisations to practise, and proceedings before the supervisory commission for health professionals and patients’ rights.

His clients include many architects, engineering firms, and companies in the construction industry. He represents them in court proceedings relating to public markets and provides legal support for all aspects of their activities.

Guillaume Etier is also passionate about art and music. He is an active member of the executive committees of several cultural organisations, including the international film festival Vision du Réel and the large Swiss circus school L'Elastique Citrique. He is also one of the co-founders of Reiser Avocats. Prior to this, he practised at the Geneva Bar for almost 15 years within leading Genevan law firms, including OHER Avocats and BRS Avocats, where he was a partner.