Montreuil has a lot a gentrification currently going on. So, even if there still quite a lot of poor people, and a huge Malian community, there is also more and more wealthy people there. And quite a lot of jobs too, with all the offices of BNP Paribas.
But, in fact, it's not really relevant here, Montreuil is where the court is, not the datacenter. The later is in La Courneuve. I know less well this city, but there it seems there is also quite a lot of gentrification and (new) jobs there.