> That's not true. No mention of 48h anywhere.

Please see https://immobilier.lefigaro.fr/article/ce-que-vous-devez-sav... and https://immobilier.lefigaro.fr/article/logement-squatte-pour...

The 48 hours are a generally applied rule for the squatters to be differentiated from, say, burglars. Because otherwise someone forcibly coming into your house while you are there could not be arrested at all.

The ones you mention is for the preéfet to statute about the expulsion.

> We have a family house that was squatted on the coast during last winter

I honestly pity you. I know of two families whose house was squatted and it took months for them to get back their house (in a terrible state); They never got anything from the quatters (nor from the insurance in one case).