Ummm, either you mixed units or your parking spots are very large.
15m² is slightly less than a 4m x 4m square, that's basically a small flat (larger than the smallest legal flat in a lot of developed countries, in fact)
I won't downvote because obviously we should be using metric, and also it was funny. However, they put it in metric first. We can't help you if you demand metric but can't figure out how big that is.
The foot isn't an SI unit, but the US influence on the internet and social media as a whole means it isn't some obscure unheard of unit. Besides, the foot has been defined by SI units for a while now, and the survey foot being done away with makes it publically official. It's just a conversion factor.
Then again being that pedantic is totally a reddit thing, so it's good to see that hasn't been lost in the migration.
While I’m just using data from the web and not actually measuring the spots in the parking lot atm, the basic size of a parking spot is 8x16 feet (128 sq feet). That works out to just over 11m^2 if Google can be trusted with the conversion.
Larger spots can go up to 10x20 feet which would work out to just over 18m^2.
And a 4mx4m room is not a small flat, that’s a small room in a small flat. But we may have cultural differences in what we determine small here.
I truly don’t think I can believe this. That’s exponentially tiny, smaller than my childhood bedroom and that room was 10x5ft (3 x 2) which was a single bedroom, not having to accommodate space for a toilet, shower, kitchen, counters, etc. I barely had a dresser and a twin bed in that room
The smallest living space you're allowed to put for sale/rent in France is 9m², and those absolutely are a thing. They're very common for example for student housing, but also former maid quarters, especially in older buildings.
The English Housing Act considers that one person living in a 70sqft room makes it legally "overcrowded", although there aren't any legal minimal sizes to sell or rent a flat.