Beachcombing is a relaxing activity the whole family can enjoy. So, why not take the kids to Parc Balneaire du Prado to see what you can find on the shoreline?
You'll find this stretch of coastline in 8th Arrondissement. Once you've seen everything you can at Parc Balneaire du Prado, have a look at nearby Notre-Dame de la Garde, Chateau d'If, and La Vieille Charite.