Murder in Montparnasse : a Phryne Fisher mystery / Kerry Greenwood.

Enhanced descriptions from Syndetics:

Always enticing in divine twenties fashion, Phryne, one of the most exciting and likeable heroines in crime writing today, leads us through a tightly plotted maze of thrilling adventure set in 1920s Australia. The divine Phryne Fisher returns to lead another dance of intrigue. Seven Australian soldiers, carousing in Paris in 1918, unknowingly witness a murder and their presence has devastating consequences. Ten years later, two are dead ... under very suspicious circumstances. Phryne's wharfie mates, Bert and Cec, appeal to her for help. They were part of this group of soldiers in 1918 and they fear for their lives and for those of the other three men. It's only as Phryne delves into the investigation that she, too, remembers being in Montparnasse on that very same day. While Phryne is occupied with memories of Montparnasse past and the race to outpace the murderer, she finds troubles of a different kind at home. Her lover, Lin Chung, is about to be married. And the effect this is having on her own usually peaceful household is disastrous.