The registration process is divided into two parts: the software publisher enrols with the ANS and later sends their application material (credentials). You may enrol any time before sending your credentials. Once your registration is validated, a web repository will be activated for you to upload your credentials in relation to your chosen DSR sector.
Yes, the applications close before the end of the first Ségur wave to allow enough time for the solutions implementation.
The Ségur works in two waves: Referencing and Installation.
The two periods are intwined and the Installation phase ends after the Referencing phase. The precise calendars are published within 15 days.