Not quite that clear cut. When you lease an apartment that becomes your domicile. Yes there are limitations but there are also legal protections.
“When you lease an apartment that becomes your domicile. “
The owner can put reasonable limits on the number of occupants. In this case, he has set a limit of four, one per bedroom.
“When you lease an apartment that becomes your domicile.”
She is not leasing the apartment. She is leasing one bedroom in the apartment.