Matching a value with every element of a set of values - Postgresql
This kind of query is called a relational division, where you "divide" film_country by country to obtain a "quotient" that represents a number of films, and then filter out on this number.

The canonical way to write it would be:

SELECT name FROM film JOIN
  (SELECT id_film FROM film_country
   GROUP BY id_film
   HAVING count(*)=(select count(*) from country)
  ) s
ON (film.id_film=s.id_film);