Choosing between SASU, SAS and SARL is one of the defining decisions every founder faces in France. Director's social-security regime, taxation, governance, transferability of shares, image in the eyes of investors: each form has its own logic and its own pitfalls. This guide compares the three structures honestly in 2026, illustrates them with real cases, and identifies the structure best suited to each entrepreneur profile — from the solo founder to the start-up preparing a