He was president of the Société des Autoroutes Paris-Normandie and the Société Française d'Archéologie. In 2016–2017, he chaired the Association des sociétés françaises d'autoroutes.[5]
As well as his career as an engineer, Mesqui pursued research on built heritage.[citation needed]
Jean Mesqui is an internationally renowned castellologist.[6] He specialises in the study of the most emblematic castles of France and the Middle East.[7] He is also considered a specialist in bridges,[7] in particular those of the Middle Ages.[8]
Jean Mesqui has written several books on medieval fortified architecture, the history of bridges and roads, and numerous articles.[9]