The Jardin des Tuileries is one of Paris's most visited gardens thanks to its central location between the Louvre and Place de la Concorde. As such the Tuileries are part of a grand central axis leading from the Louvre all the way to La Défense, the city's business district.
In the early 16th century the area was a clay quarry for tiles (tuilerie in French, hence the name). After the death of her husband Henri II in 1559, Catherine de Médicis had a Palace built at the tuileries, the Palais de Tuileries. The palace featured a large garden in Italian style, reminding her of her native Tuscany.
Kids can also enjoy the playground located centrally in the park where many a mum brings their children to play and meet up with other parisienne kids, of course all are dressed so trendily. My son found the play area great fun, even down to the water pump, beats a bubbler..
The Librarie des Jardins is a little gem set near the gates of the garden where I found some great examples of botanic illustrations dating back centuries. They also have a good collection of childrens illustrated books.