Just a thought - but if you are looking to create a quasi-institutional resdiential 'home' (and I'd guess this may have something to do with the tragedy of orphaned migrants); you may find it more appropriate looking for de-commisssioned care homes, prisons, schools or hospitals - often declared surplus to requirement / incapable of adaption to modern H & S regs etc.
Try your Mairie(s) to see what they might have / be aware of, or equally get into the Social Services teams; charitable organisations; - I'm guessing there are a myriad of different departments which hold property assets in the public domain..... or how about the churches..... the Catholic church may have some children's homes they want to offload ( 'nuff sed!)...or superannuated supermarkets - there is no shortage of empty buildings looking for new uses.....
Unless you pay a retainer to an "estate agent" to search for and acquire a suitable property; you will have to wear out some (electronic) shoe leather.
Good luck for this project.