French and German with Sherlock Holmes

I'm reading a Sherlock Holmes book, "The Sign of the Four" (the 1994 Book Club edition, if that helps) and I've come across some phrases in French and German. Since I don't speak either, I thought I'd seek help from the experts- but I'm reading this for fun, so just a general translation will be more than enough.

French

1.) Le mauvais goût mène au crime

2.) Il n'y a pas des sots si icommodes que ceux qui ont de l'esprit

German

3.) Wir sind gewohnt dass die Menschen verhöhnen was sie nicht verstehen (which is possibly a quote by Goethe)

Thanks so much!