Those metal shutters, that black out the whole room? They have those in Portugal, Spain, most of the mid-southwest Mediterranean. France also. But they’re basically ubiquitous in Portugal. Pretty nifty actually.
Edit: This was driving me nuts, sorry, but I couldn’t find a single good image of what I mean. Here’s the best I could make the robot monkey do (YMMV):
It sounds like you’re describing “Persianas” – a term used in Portugal (and other Spanish or Portuguese-speaking countries) for a specific type of heavy-duty indoor blinds or shutters. These are not the thin metal or fabric blinds but rather thick, often horizontal slats that can be rolled down to cover windows or doors completely, providing excellent light blockage and insulation.