From Amy Thomas, author of Paris, My Sweet. A love affair with Paris, New York, sweets and, now, a little girl named Parker.
Idiomatically speaking, it means "in person" or "in the flesh." For example: "J'ai vu Dutronc en chair et en os en Corse!"
Ah-ha! Merci for the tip. (I had to Google Dutrone, so now I've learned two Franco-bits today - merci, merci!)