Death at Versailles — Jane Jakeman

Versailles in August and the small Paris suburb is crowded with tourists visiting the Sun King's famous Chateau. Following her successful conviction of a powerful south-coast gangster, examining magistrate Cecile Galant has been transferred to the region for her own safety. Her workload is heavy: there's the aristocrat accused of shoplifting who is pleading not guilty despite the overwhelming evidence against him, the case of a girl who appears to have gone missing without trace and a bizarre incident in the grounds of the Chateau.
Whilst walking through the gardens of Versailles, Marina Cassatt, a student from Oxford, witnessed the murder of a young man. To complicate matters further, the boy she saw dying at her feet appeared to be dressed in eighteenth century costume; but by the time the police arrive on the scene all traces of the crime have disappeared. Could what Marina saw be linked to the unusual incident that took place in the Chateau grounds in 1901, when two female academics from Oxford claimed to have travelled into the past as they walked around the Petit Trianon?