The theft was carried out using a common pickpocket distraction technique where one of the executives carrying the documents quit a ticket queue (and left his briefcase) to come to the aid of his travelling companion who was being harassed by a vocal young man. When he returned, his briefcase was obviously gone, probably on its way to a competitor.
Dassault Aviation PR says no sensitive documents were taken.
This scenario is ripe for addition to a training deck on document management and how to behave in public. It’s a shame for Dassault but I’m sure their compliance department is having fun debriefing all concerned.