I cycle down past here every Thursday morning on my way to tennis. It's lovely, particularly as the leaves on the trees change colour in Autumn.
The building you see on the hill is the Pavillon de Louveciennes. In 1769 Louis XV offered the Chateau de Louveciennes to his new favourite, Mme du Barry. She thought that the château was disadvantaged by its lack of a view of the Seine, but also considered the reception areas to be inadequate. Poor thing! She thus decided to build a small separate house, overlooking the Seine, that would include reception rooms - the Pavillon de Louveciennes, above.
