I live in a rented flat over a shop, which both have the same landlord. The tenants in the shop have now placed advertising boards directly alongside my lounge window. I have objected to this: can I force the shopkeeper to take down the boards? What would happen if I took them down myself?
Generally you rent the interior, not the exterior, of a building. If the shop tenants below have put up their signs without the landlords permission he could order them to take them down. But they would probably be entitled to put up the signs if they had his permission, barring any term to the contrary in your lease. You should discuss this with landlord and check your lease. I dont think taking the signs down yourself is a good idea.