Land registry

I'd start at the local commune, ask if it's been asked for a change of use. They have to apply I think.
Also sometimes things stand empty because of issues when settling estates or divorces. Maybe they are renovating before anyone moves in.

personally I would go the easy route and next time i'm in the street and bump into one of the "comers and goers", I would just stop and ask. I'm sure if you're going to be the neighbours of the next people living there they won't mind enlightening you...

Check it out! You need to know who is living next door, especially if these are terraced houses. Might even be squatters, or something else!

"something else"?? What...aliens? Vampires?

You can search landowner details at https://landowner.co.in so you will get an idea about that land.