La Grande Arche de la Défense, worth visiting the third arche even if it is in the business district of la Défense and I see the actual building may not be available to the public until 2017. Still the area is impressive and, for a rainy day, the area also offers lots of indoor shopping. Les Quatre Temps is a large shopping mall on one side of La Grande Arche. CNIT is in an office area on the other side. La Défense is a major Île-de-France transportation hub and these shopping areas are accessible from this under ground transportation hub so La Grande Arche, Les Quatre Temps and CNIT are easily accessible by metro or RER. I tend to get lost in the FNAC (electronics) in CNIT there. A major French ‘big box,’ Auchan is in Les Quatre Temps as are most known boutiques like one of my wife’s favourites, Comptoir des Cotonniers.
Where is La Grande Arche; well from many areas in central Paris, if you see a large number of high-rise office buildings (west), that’s it. La Défense is the western terminus for Metro line 1 and a stop for my usual (since I used to live in St-Germain-en-Laye), RER, RER line A.