This seems very odd, as what I'd normally expect would be something like:
http://www.creativ-sign.com/toute-la-signaletique/plaque-de-... However, the use of lève-plaques does seem to mean that it's plasterboard. But, why specifically "de chambres"? The only explanation I can think of for the moment, is that perhaps it's a house where the walls downstairs are solid and plasterboard is only used for the upstairs bedrooms. The reason why someone might use "barres à mine, pioches, tournevis" could be if the plasterboard was already vertical and more or less in place, and just needed lifting a tiny bit.