That's 646 square feet. That's 25'5"x25'5". For an urban area, that's plenty of space. That doesn't mean literally every apartment is that small, just that small and cheap apartments are available for those who want them, and American-sized apartments with American prices are also available for those who want to pay for them.

That's one of the main reasons why housing is so expensive in the United States. We paternalistically decide that 760 square feet is the absolute minimum amount of livable space for a one-bedroom apartment, and instead force people who can't afford that much space to split a 1200 square foot apartment with three people.

Adults are more than capable of deciding for themselves how big of an apartment they would like to live in. Banning 60 square meter apartments doesn't help people who can't afford the legal mandated minimum.