I snapped this photo outside the apartment we stayed in in Paris last year! Soo many bikes and soo little space.
We are also facing the same dilemma at our house. A and I rent a small house with a massive open plan dining, kitchen and living (not many walls!) two bedrooms (with impractical built in wardrobes) and a bathroom with a euro laundry.
We have a small back yard which I park my car in and a courtyard out the front. We don't have a shed or garage. Currently our bikes are living in various places around the house including the kitchen and hallway.
As we are renting we don't have a huge amount of options for wall attachments.
I think we will have to look into portable sheds! My old bike lived under the veranda locked up out of the rain, but our new babies are worth a whole lot more so that isn't the best option!