Where to work for free in Rennes?

Coworker Malin lists 7 free places to work from in Rennes: 5 cafes, 1 restaurant or bar, and 1 library. 1 is free with nothing to buy and 6 expect you to order something. Among them, 4 with wifi and 3 with power sockets.

Where can I work in Rennes with wifi and power sockets?
2 places have both: Café 1802 and Bibliothèque des Champs Libres.
Can I stay and work for several hours in Rennes?
It depends on the place. Out of the 7 whose laptop policy is known, 3 welcome laptops, 3 tolerate them, and 1 would rather you didn't stay long. Each page spells out the house rules.
Where can I work in Rennes without buying anything?
In a library, where nothing has to be bought: Bibliothèque des Champs Libres.