> Edit: to clarify, I'm French, and this exact same modus operandi has been used by far-left movements in the past to disrupt high-speed lines; if you have solid arguments against my theory, I suggest you address them before blindly downvoting.

The only remotely similar case is Tarnac, and it is ludicrous to even compare it with what is happening today. Tarnac was one line interrupted with a very different (and less destructive) method. Today was a coordinated attack at a much wider scale in a short amount of time. You would be hard press to find any far-left organization in France with the capacity to even approach such an operation.