The clue to that one is in the French vacation letter that is fastened to the top of the box and the numbers that are written with what are supposed to be references to lines from the play, Hamlet ("Some of these don't exist").
You should have 11 letters total that you pull from the French vacation letter. The X in the Hamlet references is meaningless, but the letters that you pull from the vacation letter using the numbers from those references are in order the way that you will enter them into the lock on the box. When you are counting out the numbers from the reference don't start with the letter you just got and don't count spaces. In other words -
The first number was 1 - the first letter is L The second number was 3 so starting with the a of La count to 3 (aVe) - the second letter is E The third number was 32 so starting with the r of Vergne count to 32 (rgnewasjustwondrousthissummerWeb - the third letter is B The fourth number was 8 so starting with o of both count to 8 - (othstaye) - the fourth letter is E
So far we have LEBE - the rest of the letters that you need to open the box are found the same way -
The letter that you are going to use for the combination is the last one that you count for each number, and spaces and punctuation are not counted.
Always start counting at the letter following the one you are going to use for the combination.
When you enter the letters in the combination, they go in the order that they came from the letter. There is no unscrambling or looking for hidden words, just meaningless letters that open up the box.