Another French region will try to manage their inability to provide enough capacity by making reservations mandatory:
2 TER lines in Grand Est will have mandatory reservations from 1 July:
- Paris - Troyes - Belfort - Mulhouse
- Paris - Épernay - St. Dizier/Bar-le-Duc (possibly all the way from/to Strasbourg for the few trains that do that)
The reservations are supposed to be free of charge and available from 1 March. No idea however, how or where they can then be booked.