I've asked around, and someone pointed me to "Georges Bizet, Carmen" by Susan McClary. Here is the proof - a letter from Marie Roze to Bizet - and it contains the word "scabrous"! Also interesting to see that Offenbach's mistress Zulma Bouffar, was approached first. More about her (in French) here.

[This message has been edited by Andrew (edited 02-28-2010).]