When Bob Moyer isn’t traveling in physical terms, he’s traveling through his reading. Here, he visits Paris by way of a charming mystery. Reviewed by Robert P. Moyer MURDER BELOW MONTPARNASSE. By Cara Black. SOHO Crime. 336 pages. $25.95. Cara Black has carved a comfortable niche out of the soft-boiled genre. She rambles around Paris, concocting…