How many Summer games are there that were held in Paris?
Summer games refer to games_id where season = 'Summer'; Paris refers to city_name = 'Paris';
SELECT COUNT(T3.id) FROM games_city AS T1 INNER JOIN city AS T2 ON T1.city_id = T2.id INNER JOIN games AS T3 ON T1.games_id = T3.id WHERE T2.city_name = 'Paris' AND T3.season = 'Summer'