French cable designations

I have a thermostat going to a boiler, all destructions in French, the book has the cable labelled as L and S presumably L = live and S= neutral bearing in mind that in France the neutral is live I believe. Can anyone confirm this please

 

Maybe a false presumption

Instruction for a French machine's power connection

une borne de câble sous tension, une borne de ligne neutre et une borne de câble de mise à la terre.

borne = terminal

câble sous tension = LIVE

ligne neutre = Neutral

 

Thank you for that. So I could look at the cable going into the pcb and deduce what they are from the cable colour presuming that its wired up correctly which if you look at the central heating forum leads me onto the crux of the problem.