The Bridges in Paris — Michele Sobel Spirn

Robin and Jo Bridge are in Paris without their parents and the sinister Madame Georges as their guide and chaperone. On their first day in the City of Lights, they are given a mysterious package by a waiter. There is danger lurking in Notre-Dame, the Eiffel Tower, the Louvre, as Robin and Jo try to solve the mysteries of the dot on the map and the disappearing hospital patient.