Headlines and Titles of Works

Q. I’m helping a French writer edit a book he has written in English. I’ve been following the convention of writing French words and phrases in italics and also using italics for movie titles, book titles, etc. Now I come upon a French song title, and I can’t figure out what to do with it. Here is the phrase: He called it “La non-demande en mariage.” Do I keep the quotation marks? Do I italicize the French song title? Both?

A. Chicago puts longer French phrases and sentences in quotation marks (no italics) and reserves italics for single words and very short phrases. Poem or song titles are quoted no matter what language they’re in. Chapter 11 of CMOS has more information on editing French and other languages.

[This answer relies on the 17th edition of CMOS (2017) unless otherwise noted.]