I think you're referring to the little square bricks. I'm going to hazard a guess that it has to do with Servair in CDG. They make bread and store it for a while in those flimsy thin plastic bags, but they do it for a lot more flights than outstations, so it probably gets stored for a lot longer.

The PNC's will heat their own bread in the oven, but it's hard to do this for everybody because they come in either the basket or bags and PNC baking skills are questionable (burnt croissants, anyone?)

You could ask them and they'd probably stick it in the oven and heat it up for you to soften it...