The CEA has sports and cultural societies that either organise classes and visits or reimburse expenses such as concerts, theatre, museum entrances, etc… See the Benefits section for details.
Bibliothèque nationale de France: less busy than the BPI but you have to buy a day pass for 3.50 euros or an annual pass for 38 euros. Power points everywhere, no Wifi but ethernet cables on some desks
Most museums and art galleries in Paris are free the first Sunday of every month. Most of the Paris municipal museums are free all of the time. Lots of things are free if you are under 26. If you’re going to the Louvre, enter via the shopping mall ‘Carrousel du Louvre’ to save queueing time
Seat61: All the info and pictures you could ever need for planning international train travel starting from Paris: http://www.seat61.co.uk
Capitaine Train: Site that searches across all the different train ticket types to find the best deal: https://www.capitainetrain.com/