In particular the Author deals with the specific issue of cross-border seatmovement of companies, discussing the principal international private lawtheories as well as the ECJ case-law milestones on the freedom ofestablishment (art. 43 EC Treaty) - such as Daily Mail case, Sevic case,Uberseering case, Centros case and Inspire Art case. In conclusion hetreats the turning point case given by Cartesio case and the consequencesit had on the development of Societas Europae (SE) doctrine: a common lexsocietatis europae isn't still a chimera