The Church published the Index Librorum Prohibitorum (ie, List of Prohibited Books) beginning in 1559. The index was abolished in 1966, and has not been "in force" since. To my knowledge, the index applied only to books - I am not aware of any motion pictures that were ever included.
The Church has never claimed that it is an ipso facto mortal sin to read any book on the index. Nor has the Church ever claimed that it is an ipso facto sin to go to a pub. But both can lead to mortal sin, depending on the disposition of the individual. This is known as the "near occasion" of sin - the person might not intend to sin, but willfully places himself in a situation where temptation is strong (dancing naked girls). Maybe Candide is such a temptation (though it seems pretty lame to our "modern" sensibilities).