Here is a (not exhaustive) list of possible website of interest.

Housing in Paris region:

Science accueil: https://www.science-accueil.org/en/
Cité Universitaire: https://www.ciup.fr/en/
Maison de l'Italie: https://maison-italie.org/wordpress/

Hotels nearby L2S:

HOTEL CAMPANILE PARIS - Saclay (200m distance to L2S)
Residhome Bures la Guyonnerie(1.1km distance to L2S)
Hotel d'Orsay in Orsay (2.5km distance to L2S and 15 min by public transportation)
Aparthotel Adagio access Palaiseau Saclay (3.5km distance to L2S and 15-20 min by public transportation)
Hôtel Novotel Paris Saclay (5km distance to L2S and 25-30 min by public transportation)

Visit Paris region:

https://www.visitparisregion.com/en
https://en.parisinfo.com/