I found the script for "Killing Zoe", this is the way it goes:

Zed-"Well, I like your honesty. You're open. Unlike most prostitutes I've been with.'

She doesn't like the sound of this. She slaps him.

Zoe-"I am not a prostitute!"

Zed is a little surprised at this.

Zed-"Really? Can I have my francs back then?"