Hauts-de-Seine (92) and Yvelines (78)
The west of Paris is rich in activities and family outings. Among the ideas for cultural outings: the National Archaeology Museum of Saint Germain en Laye (famous for its department dedicated to prehistory), three castles including the unmissable Palace of Versailles.
We really like the France Miniature amusement park to discover French heritage in a fun way.