MIAMI—The Little Haiti neighborhood has never held much appeal to real-estate developers. Its inland location is flanked by railroad tracks and an interstate highway. It has long been home to working-class Haitian and other immigrants and mom-and-pop shops that cater to them.

Now, due in part to the area’s higher elevation in a city vulnerable to rising sea-levels, more property firms are flocking to Little Haiti. Investors are scooping up homes and industrial lots. Others are building office towers, trendy restaurants and...