Don Giovanni and Cardillac are not both operas with three acts.
Don Giovanni (] ; K. 527; complete title: "Il dissoluto punito, ossia il Don Giovanni" , literally "The Rake Punished, namely Don Giovanni" or "The Libertine Punished") is an opera in two acts with music by Wolfgang Amadeus Mozart and Italian libretto by Lorenzo Da Ponte. 
Cardillac is an opera by Paul Hindemith in three acts and four scenes. 
