[pstrg]

I think you've overlook something on the default sort tokens: it's a \W not a \w. That means all no word character. That does not include _ and that's the reason why it's also listed.
the[\W_] catches "The Case" but not "Theory". For your case with "L'Armée des ombres" you've to add l'.

Der .* is completly wrong and will catch the whole title if the title starts with "Der", e.g. "Der Bergdoktor".

FYI: a ^ will be added automatically to each token to only catch the token if it's on the beginning of the title. Also "ignore case" is enabled for token regex.

You're right. My mistake.