Originally Posted by carnarvon

I second Goldorak's comment : not time for lunch. I would rather suggest breakfast in a nice hotel with a view.

Rather than head to the Champs-Elysees and waste time with a connection in the station "Chatelets-Les Halles", why not stay on the train line RER B and go one stop further to St Michel-Notre Dame.

Walk 10 mn to the hotel Cheval Blanc and have breakfast there. It is not cheap, but the views are worth it. Much classier than the Champs-Elysees.

If not within your budget, there are many hotels and restaurants in St Michel area.

P.S. You can get off at Chatelet-Les Halles and save one stop, but the walk would be somehow less interesting than from Saint-Michel, not to mention the risk of choosing the wrong exit (there are loads of them in this huge station).