That's a good question and without knowing population data at the time the city hosted the Games that is a tough one to answer. However, of all cities to host the Olympics the current smallest is Lake Placid in the USA whose population was reported in the 2000 census at 2,638. Lake Placid hosted the 1932 and 1980 Winter Olympics.
In 1960 squaw valley hosted the winter Olympics, its an unincorporated town in California, might be smaller than lake Placid
London, United Kingdom is the host city of the 2012 Olympic Games.
Seoul was the first city to host the Summer Olympic Games. In 1806.
Mexico City
rio
Mexico City
London
Paris
In the next host city.
London
Stockholm
None
Paris