Are there any power outlets available inside SNCF's Intercités de Nuit? Ideally I'd like to know about both second and first class sleeper compartments, and any other possible locations.
According to this post on the forum of the french railway company SNCF, you can find power oulets in the hallway. Even the incleanable seats do not feature power outlets.
If you plan to use the plugs in the hallway, a good idea suggested by this blog is to take a power strip along with you. Indeed, you may not be the only one in need of a plug!
No, I'm afraid there are no power outlets in these trains except in the bathrooms & in the hallway... You can still take a portable battery with you to charge your phone... during the night.