The little Chihuahua also feels at home in an apartment and does not require a lot of space or a garden. Although he would certainly not object to his own plot of land to run around and play.
The smallest dog breed in the world actually only has small space requirements and if the four-legged friend is sufficiently mentally and physically busy, a city apartment or a room in a shared flat is certainly not a problem.
But please don’t put the litter box or the puppy toilet in a corner and consider the Chihuahua purely as an apartment dog. He has the same needs as a giant mastiff and should be allowed to walk, run, sniff, and detach at least three times a day.