To develop quickly and without unnecessary constraints, the form must be stable and flexible enough to face all situations across time. SAS (société par actions simplifiée) is the most flexible form of company that lets you change your organisation as you grow.
For example, you can decide on majorities during general assembly votes, you can decide how to allocate bonus shares to your employees, you can change the rights of officers or share capital, and so on. With the SAS or SASU, the majority of the daily actions over the life of your company can be decided in a general assembly without having recourse to experts.
For example, the capital contribution of 1 euro minimum avoids immobilizing your capital at the launch of your company (the minimum for the SA is 37,500 euros); the possibility of having only one partner (as opposed to the 7 or 2 partners minimum for the SA) makes it possible to start quickly and to decide on the organization of the company simply according to your growth and governance rules.