Through the village of Chevreuse runs a tiny offshoot of the Yvette river, gently traversing timeworn cottages, ancient wash-houses, and a medieval tannery. There are 22 “petits ponts,” “little bridges,” that span the river, crossing various pathways. A popular walk for locals and visitors, this promenade is hidden behind high fences sandwiched between the backs (or fronts) of perennial houses and a modern car park. Perhaps the best times of the year to visit are during the spring, when the blossoms and jonquils perform their brief but beautiful annual display, and…